Trace number 3322101

Some explanations

A solver is run under the control of another program named runsolver. runsolver is in charge of imposing the CPU time limit and the memory limit to the solver. It also monitors some information about the process. The trace of the execution of a solver is divided into four (or five) parts:
  1. SOLVER DATA
    This is the output of the solver (stdout and stderr).
    Note that some very long lines in this section may be truncated by your web browser ! In such a case, you may want to use the "Download as text" link to get the trace as a text file.

    When the --timestamp option is passed to the runsolver program, each line output by the solver is prepended with a timestamp which indicates at what time the line was output by the solver. Times are relative to the start of the program, given in seconds. The first timestamp (if present) is estimated CPU time. The last timestamp is wall clock time.

    As some 'v lines' may be very long (sometimes several megabytes), the 'v line' output by your solver may be split on several lines to help limit the size of the trace recorded in the database. In any case, the exact output of your solver is preserved in a trace file.
  2. VERIFIER DATA
    The output of the solver is piped to a verifier program which will search a value line "v " and, if found, will check that the given interpretation satisfies all constraints.
  3. CONVERSION SCRIPT DATA (Optionnal)
    When a conversion script is used, this section shows the messages that were output by the conversion script.
  4. WATCHER DATA
    This is the informations gathered by the runsolver program. It first prints the different limits. There's a first limit on CPU time set to X seconds (see the parameters in the trace). After this time has ellapsed, runsolver sends a SIGTERM and 2 seconds later a SIGKILL to the solver. For safety, there's also another limit set to X+30 seconds which will send a SIGXPU to the solver. The last limit is on the virtual memory used by the process (see the parameters in the trace).
    Every ten seconds, the runsolver process fetches the content of /proc/loadavg, /proc/pid/stat and /proc/pid/statm (see man proc) and prints it as raw data. This is only recorded in case we need to investigate the behaviour of a solver. The memory used by the solver (vsize) is also given every ten seconds.
    When the solver exits, runsolver prints some informations such as status and time. CPU usage is the ratio CPU Time/Real Time.
  5. LAUNCHER DATA
    These informations are related to the script which will launch the solver. The most important informations are the command line given to the solver, the md5sum of the different files and the dump of the /proc/cpuinfo and /proc/meminfo which provides some useful information on the computer.

Solver answer on this benchmark

Solver NameAnswerCPU timeWall clock time
borg-sat 11.03.02-randomSAT 1.90671 1.09057

General information on the benchmark

Namerandom/medium/
unif-k3-r4.26-v450-c1917-S528475885-007.SATISFIABLE.cnf
MD5SUM970ca2029fea75cb0f7721dfc724b428
Bench CategoryRANDOM (random instances)
Best result obtained on this benchmarkSAT
Best CPU time to get the best result obtained on this benchmark0.053991
Satisfiable
(Un)Satisfiability was proved
Number of variables450
Number of clauses1917
Sum of the clauses size5751
Maximum clause length3
Minimum clause length3
Number of clauses of size 10
Number of clauses of size 20
Number of clauses of size 31917
Number of clauses of size 40
Number of clauses of size 50
Number of clauses of size over 50

Solver Data

0.35/0.67	c INFO: loaded portfolio from HOME/etc/borg-mix+class.random.pickle
0.35/0.67	c INFO: solving HOME/instance-3322101-1304374430.cnf
0.35/0.67	c INFO: computing task features
0.35/0.68	c INFO: computed variable-clause graph statistics
0.35/0.68	c INFO: computed clause balance statistics
0.44/0.71	c INFO: computed variable balance statistics
0.44/0.74	c INFO: computed small-clause counts
0.44/0.74	c INFO: computed Horn-clause counts
0.44/0.74	c INFO: computed variable graph statistics
0.44/0.74	c INFO: collected features for HOME/instance-3322101-1304374430.cnf in 0.07 s
0.44/0.78	c INFO: running gnovelty+2@0 for 97 with 39999 remaining (b = 0.56)
0.53/0.82	c INFO: running march_hi@0 for 388 with 39999 remaining (b = 0.36)
0.53/0.85	c INFO: running march_hi@0 for 388 with 39999 remaining (b = 0.32)
0.53/0.89	c INFO: running march_hi@0 for 97 with 39999 remaining (b = 0.11)
0.63/0.93	c INFO: running gnovelty+2@0 for 97 with 39999 remaining (b = 0.07)
0.63/0.97	c INFO: running march_hi@0 for 485 with 39999 remaining (b = 0.26)
0.73/1.01	c INFO: running march_hi@0 for 485 with 39999 remaining (b = 0.23)
0.73/1.05	c INFO: running march_hi@0 for 485 with 39999 remaining (b = 0.21)
0.73/1.06	s SATISFIABLE
0.73/1.06	v -1 -2 -3 -4 5 -6 -7 -8 -9 -10 11 12 -13 -14 -15 16 17 18 19 20 21 22 -23 -24 -25 -26 27 28 -29 30 -31 -32 -33 34 35 -36 37 -38 39 -40 41 -42 -43 44 -45 46 -47 48 -49 50 51 -52 -53 54 -55 -56 57 -58 -59 -60 61 -62 63 64 65 66 67 -68 -69 -70 71 -72 -73 74 -75 -76 77 78 79 80 81 -82 -83 84 85 -86 -87 88 -89 90 91 92 93 94 95 96 -97 98 99 100 -101 -102 103 -104 -105 106 107 -108 -109 110 111 112 -113 114 115 -116 -117 -118 -119 120 121 122 123 -124 -125 -126 -127 -128 -129 -130 131 132 -133 -134 -135 136 137 138 139 140 141 142 -143 144 145 146 147 -148 -149 -150 -151 -152 153 154 -155 156 -157 -158 159 -160 161 162 -163 -164 -165 166 -167 168 169 170 171 -172 -173 -174 175 -176 177 -178 179 180 -181 182 -183 -184 185 -186 -187 188 -189 -190 -191 -192 -193 -194 -195 -196 -197 198 199 -200 201 -202 -203 204 -205 -206 -207 -208 -209 -210 211 212 -213 -214 -215 -216 -217 -218 219 220 221 -222 -223 -224 225 226 227 228 229 230 231 232 -233 -234 -235 -236 237 -238 239 240 -241 242 243 244 -245 -246 247 248 -249 250 251 252 253 254 -255 -256 257 258 259 -260 -261 262 -263 -264 -265 266 267 268 269 -270 271 -272 273 274 275 276 -277 278 -279 280 281 -282 -283 -284 285 286 -287 288 -289 290 291 292 -293 -294 295 296 297 298 -299 300 301 302 -303 -304 305 306 307 -308 -309 -310 -311 -312 -313 314 -315 -316 -317 -318 319 320 321 322 -323 324 -325 326 -327 328 -329 -330 -331 -332 -333 -334 -335 336 337 338 -339 340 -341 342 343 -344 345 346 347 348 349 -350 351 352 353 354 -355 356 357 358 359 -360 361 362 -363 -364 -365 -366 367 368 369 370 -371 -372 -373 -374 -375 376 377 378 -379 -380 381 -382 383 384 385 -386 387 -388 -389 -390 391 -392 393 -394 395 396 397 -398 -399 -400 -401 402 403 404 -405 406 -407 -408 -409 410 411 -412 413 414 415 416 -417 -418 419 420 421 422 423 -424 425 -426 -427 -428 429 430 -431 432 433 434 -435 -436 437 -438 -439 -440 -441 -442 -443 -444 -445 446 447 448 449 -450 0

Verifier Data

OK

Watcher Data

runsolver Copyright (C) 2010-2011 Olivier ROUSSEL

This is runsolver version 3.3.0 (svn: 935)

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

command line: BIN/runsolver --timestamp -w /tmp/evaluation-result-3322101-1304374430/watcher-3322101-1304374430 -o /tmp/evaluation-result-3322101-1304374430/solver-3322101-1304374430 -C 40000 -W 5100 -M 31000 python HOME/solve HOME/etc/borg-mix+class.random.pickle HOME/instance-3322101-1304374430.cnf -seed 1009796291 -budget 40000 -cores 8 

running on 8 cores: 0,2,4,6,1,3,5,7

Enforcing CPUTime limit (soft limit, will send SIGTERM then SIGKILL): 40000 seconds
Enforcing CPUTime limit (hard limit, will send SIGXCPU): 40030 seconds
Enforcing wall clock limit (soft limit, will send SIGTERM then SIGKILL): 5100 seconds
Enforcing VSIZE limit (soft limit, will send SIGTERM then SIGKILL): 31744000 KiB
Enforcing VSIZE limit (hard limit, stack expansion will fail with SIGSEGV, brk() and mmap() will return ENOMEM): 31795200 KiB
Current StackSize limit: 10240 KiB


[startup+0 s]
/proc/loadavg: 8.51 9.12 9.54 2/288 8642
/proc/meminfo: memFree=17414276/32950928 swapFree=67111528/67111528
[pid=8642] ppid=8640 vsize=15776 CPUtime=0 cores=0-7
/proc/8642/stat : 8642 (python) R 8640 8642 8616 0 -1 4202496 873 0 0 0 0 0 0 0 25 0 1 0 5052396 16154624 754 33554432000 4194304 5683644 140735243460192 18446744073709551615 4540219 0 0 16781312 2 0 0 0 17 4 0 0 0
/proc/8642/statm: 3944 755 343 364 0 431 0

[startup+0.10723 s]
/proc/loadavg: 8.51 9.12 9.54 2/288 8642
/proc/meminfo: memFree=17414276/32950928 swapFree=67111528/67111528
[pid=8642] ppid=8640 vsize=94180 CPUtime=0.05 cores=0-7
/proc/8642/stat : 8642 (python) S 8640 8642 8616 0 -1 4202496 2768 0 0 0 4 1 0 0 25 0 1 0 5052396 96440320 2475 33554432000 4194304 5683644 140735243460192 18446744073709551615 218880563200 0 2147483391 16781312 2 18446744071699199166 0 0 17 4 0 0 0
/proc/8642/statm: 23545 2475 764 364 0 1677 0
Current children cumulated CPU time (s) 0.05
Current children cumulated vsize (KiB) 94180

[startup+0.201219 s]
/proc/loadavg: 8.51 9.12 9.54 2/288 8642
/proc/meminfo: memFree=17414276/32950928 swapFree=67111528/67111528
[pid=8642] ppid=8640 vsize=124236 CPUtime=0.13 cores=0-7
/proc/8642/stat : 8642 (python) R 8640 8642 8616 0 -1 4202496 4276 0 1 0 9 4 0 0 25 0 1 0 5052396 127217664 3881 33554432000 4194304 5683644 140735243460192 18446744073709551615 218880385429 0 0 16781312 2 0 0 0 17 4 0 0 0
/proc/8642/statm: 31059 3881 997 364 0 2870 0
Current children cumulated CPU time (s) 0.13
Current children cumulated vsize (KiB) 124236

[startup+0.3012 s]
/proc/loadavg: 8.51 9.12 9.54 2/288 8642
/proc/meminfo: memFree=17414276/32950928 swapFree=67111528/67111528
[pid=8642] ppid=8640 vsize=135752 CPUtime=0.18 cores=0-7
/proc/8642/stat : 8642 (python) S 8640 8642 8616 0 -1 4202496 5965 935 1 0 13 5 0 0 17 0 1 0 5052396 139010048 4152 33554432000 4194304 5683644 140735243460192 18446744073709551615 218880561157 0 2147483391 16781312 2 18446744071699199166 0 0 17 4 0 0 0
/proc/8642/statm: 33938 4152 1032 364 0 3124 0
Current children cumulated CPU time (s) 0.18
Current children cumulated vsize (KiB) 135752

[startup+0.70112 s]
/proc/loadavg: 8.51 9.12 9.54 2/288 8642
/proc/meminfo: memFree=17414276/32950928 swapFree=67111528/67111528
[pid=8642] ppid=8640 vsize=278296 CPUtime=0.44 cores=0-7
/proc/8642/stat : 8642 (python) R 8640 8642 8616 0 -1 4202496 9311 935 1 0 32 12 0 0 16 0 1 0 5052396 284975104 6981 33554432000 4194304 5683644 140735243460192 18446744073709551615 47131555739339 0 0 16781312 2 0 0 0 17 4 0 0 0
/proc/8642/statm: 69574 6981 1826 364 0 5498 0
Current children cumulated CPU time (s) 0.44
Current children cumulated vsize (KiB) 278296

Solver just ended. Dumping a history of the last processes samples

[startup+0.801141 s]
/proc/loadavg: 8.51 9.12 9.54 2/288 8642
/proc/meminfo: memFree=17414276/32950928 swapFree=67111528/67111528
[pid=8642] ppid=8640 vsize=289280 CPUtime=0.53 cores=0-7
/proc/8642/stat : 8642 (python) R 8640 8642 8616 0 -1 4202496 10219 935 1 0 41 12 0 0 18 0 2 0 5052396 296222720 7207 33554432000 4194304 5683644 140735243460192 18446744073709551615 218884003811 0 0 16781312 2 18446744073709551615 0 0 17 4 0 0 0
/proc/8642/statm: 72320 7207 1874 364 0 8238 0
Current children cumulated CPU time (s) 0.53
Current children cumulated vsize (KiB) 289280

[startup+1.00099 s]
/proc/loadavg: 8.51 9.12 9.54 2/288 8642
/proc/meminfo: memFree=17414276/32950928 swapFree=67111528/67111528
[pid=8642] ppid=8640 vsize=406300 CPUtime=0.73 cores=0-7
/proc/8642/stat : 8642 (python) R 8640 8642 8616 0 -1 4202496 14341 935 1 0 60 13 0 0 21 0 7 0 5052396 416051200 7411 33554432000 4194304 5683644 140735243460192 18446744073709551615 4533119 0 0 16781312 2 18446744073709551615 0 0 17 4 0 0 0
/proc/8642/statm: 101575 7411 1884 364 0 37478 0
Current children cumulated CPU time (s) 0.73
Current children cumulated vsize (KiB) 406300

Child status: 0
Real time (s): 1.09057
CPU time (s): 1.90671
CPU user time (s): 1.70774
CPU system time (s): 0.198969
CPU usage (%): 174.836
Max. virtual memory (cumulated for all children) (KiB): 406300

getrusage(RUSAGE_CHILDREN,...) data:
user time used= 1.70774
system time used= 0.198969
maximum resident set size= 0
integral shared memory size= 0
integral unshared data size= 0
integral unshared stack size= 0
page reclaims= 30688
page faults= 1
swaps= 0
block input operations= 0
block output operations= 0
messages sent= 0
messages received= 0
signals received= 0
voluntary context switches= 3049
involuntary context switches= 80

runsolver used 0.005999 second user time and 0.016997 second system time

The end

Launcher Data

Begin job on node112 at 2011-05-03 00:13:50
IDJOB=3322101
IDBENCH=82879
IDSOLVER=1712
FILE ID=node112/3322101-1304374430
RUNJOBID= node112-1304374430-8630
PBS_JOBID= 13181779
Free space on /tmp= 72380 MiB

SOLVER NAME= borg-sat 11.03.02-random
BENCH NAME= SAT11/random/medium/unif-k3-r4.26-v450-c1917-S528475885-007.SATISFIABLE.cnf
COMMAND LINE= python DIR/solve DIR/etc/borg-mix+class.random.pickle BENCHNAME -seed RANDOMSEED -budget TIMEOUT -cores NBCORE
RUNSOLVER COMMAND LINE= BIN/runsolver --timestamp -w /tmp/evaluation-result-3322101-1304374430/watcher-3322101-1304374430 -o /tmp/evaluation-result-3322101-1304374430/solver-3322101-1304374430 -C 40000 -W 5100 -M 31000  python HOME/solve HOME/etc/borg-mix+class.random.pickle HOME/instance-3322101-1304374430.cnf -seed 1009796291 -budget 40000 -cores 8

TIME LIMIT= 40000 seconds
MEMORY LIMIT= 31000 MiB
NBCORE= 8

MD5SUM BENCH= 970ca2029fea75cb0f7721dfc724b428
RANDOM SEED=1009796291

node112.alineos.net Linux 2.6.18-164.el5 #1 SMP Thu Sep 3 03:28:30 EDT 2009

/proc/cpuinfo:
processor	: 0
vendor_id	: GenuineIntel
cpu family	: 6
model		: 26
model name	: Intel(R) Xeon(R) CPU           X5550  @ 2.67GHz
stepping	: 5
cpu MHz		: 2666.847
cache size	: 8192 KB
physical id	: 0
siblings	: 4
core id		: 0
cpu cores	: 4
apicid		: 0
fpu		: yes
fpu_exception	: yes
cpuid level	: 11
wp		: yes
flags		: fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm syscall nx rdtscp lm constant_tsc ida nonstop_tsc pni monitor ds_cpl vmx est tm2 cx16 xtpr popcnt lahf_lm
bogomips	: 5333.69
clflush size	: 64
cache_alignment	: 64
address sizes	: 40 bits physical, 48 bits virtual
power management: [8]

processor	: 1
vendor_id	: GenuineIntel
cpu family	: 6
model		: 26
model name	: Intel(R) Xeon(R) CPU           X5550  @ 2.67GHz
stepping	: 5
cpu MHz		: 2666.847
cache size	: 8192 KB
physical id	: 1
siblings	: 4
core id		: 0
cpu cores	: 4
apicid		: 16
fpu		: yes
fpu_exception	: yes
cpuid level	: 11
wp		: yes
flags		: fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm syscall nx rdtscp lm constant_tsc ida nonstop_tsc pni monitor ds_cpl vmx est tm2 cx16 xtpr popcnt lahf_lm
bogomips	: 5180.45
clflush size	: 64
cache_alignment	: 64
address sizes	: 40 bits physical, 48 bits virtual
power management: [8]

processor	: 2
vendor_id	: GenuineIntel
cpu family	: 6
model		: 26
model name	: Intel(R) Xeon(R) CPU           X5550  @ 2.67GHz
stepping	: 5
cpu MHz		: 2666.847
cache size	: 8192 KB
physical id	: 0
siblings	: 4
core id		: 1
cpu cores	: 4
apicid		: 2
fpu		: yes
fpu_exception	: yes
cpuid level	: 11
wp		: yes
flags		: fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm syscall nx rdtscp lm constant_tsc ida nonstop_tsc pni monitor ds_cpl vmx est tm2 cx16 xtpr popcnt lahf_lm
bogomips	: 5332.76
clflush size	: 64
cache_alignment	: 64
address sizes	: 40 bits physical, 48 bits virtual
power management: [8]

processor	: 3
vendor_id	: GenuineIntel
cpu family	: 6
model		: 26
model name	: Intel(R) Xeon(R) CPU           X5550  @ 2.67GHz
stepping	: 5
cpu MHz		: 2666.847
cache size	: 8192 KB
physical id	: 1
siblings	: 4
core id		: 1
cpu cores	: 4
apicid		: 18
fpu		: yes
fpu_exception	: yes
cpuid level	: 11
wp		: yes
flags		: fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm syscall nx rdtscp lm constant_tsc ida nonstop_tsc pni monitor ds_cpl vmx est tm2 cx16 xtpr popcnt lahf_lm
bogomips	: 5332.82
clflush size	: 64
cache_alignment	: 64
address sizes	: 40 bits physical, 48 bits virtual
power management: [8]

processor	: 4
vendor_id	: GenuineIntel
cpu family	: 6
model		: 26
model name	: Intel(R) Xeon(R) CPU           X5550  @ 2.67GHz
stepping	: 5
cpu MHz		: 2666.847
cache size	: 8192 KB
physical id	: 0
siblings	: 4
core id		: 2
cpu cores	: 4
apicid		: 4
fpu		: yes
fpu_exception	: yes
cpuid level	: 11
wp		: yes
flags		: fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm syscall nx rdtscp lm constant_tsc ida nonstop_tsc pni monitor ds_cpl vmx est tm2 cx16 xtpr popcnt lahf_lm
bogomips	: 5332.61
clflush size	: 64
cache_alignment	: 64
address sizes	: 40 bits physical, 48 bits virtual
power management: [8]

processor	: 5
vendor_id	: GenuineIntel
cpu family	: 6
model		: 26
model name	: Intel(R) Xeon(R) CPU           X5550  @ 2.67GHz
stepping	: 5
cpu MHz		: 2666.847
cache size	: 8192 KB
physical id	: 1
siblings	: 4
core id		: 2
cpu cores	: 4
apicid		: 20
fpu		: yes
fpu_exception	: yes
cpuid level	: 11
wp		: yes
flags		: fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm syscall nx rdtscp lm constant_tsc ida nonstop_tsc pni monitor ds_cpl vmx est tm2 cx16 xtpr popcnt lahf_lm
bogomips	: 5332.83
clflush size	: 64
cache_alignment	: 64
address sizes	: 40 bits physical, 48 bits virtual
power management: [8]

processor	: 6
vendor_id	: GenuineIntel
cpu family	: 6
model		: 26
model name	: Intel(R) Xeon(R) CPU           X5550  @ 2.67GHz
stepping	: 5
cpu MHz		: 2666.847
cache size	: 8192 KB
physical id	: 0
siblings	: 4
core id		: 3
cpu cores	: 4
apicid		: 6
fpu		: yes
fpu_exception	: yes
cpuid level	: 11
wp		: yes
flags		: fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm syscall nx rdtscp lm constant_tsc ida nonstop_tsc pni monitor ds_cpl vmx est tm2 cx16 xtpr popcnt lahf_lm
bogomips	: 5332.74
clflush size	: 64
cache_alignment	: 64
address sizes	: 40 bits physical, 48 bits virtual
power management: [8]

processor	: 7
vendor_id	: GenuineIntel
cpu family	: 6
model		: 26
model name	: Intel(R) Xeon(R) CPU           X5550  @ 2.67GHz
stepping	: 5
cpu MHz		: 2666.847
cache size	: 8192 KB
physical id	: 1
siblings	: 4
core id		: 3
cpu cores	: 4
apicid		: 22
fpu		: yes
fpu_exception	: yes
cpuid level	: 11
wp		: yes
flags		: fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm syscall nx rdtscp lm constant_tsc ida nonstop_tsc pni monitor ds_cpl vmx est tm2 cx16 xtpr popcnt lahf_lm
bogomips	: 5332.83
clflush size	: 64
cache_alignment	: 64
address sizes	: 40 bits physical, 48 bits virtual
power management: [8]


/proc/meminfo:
MemTotal:     32950928 kB
MemFree:      17414556 kB
Buffers:         87796 kB
Cached:        1381720 kB
SwapCached:          0 kB
Active:       14256816 kB
Inactive:      1113388 kB
HighTotal:           0 kB
HighFree:            0 kB
LowTotal:     32950928 kB
LowFree:      17414556 kB
SwapTotal:    67111528 kB
SwapFree:     67111528 kB
Dirty:           31860 kB
Writeback:           0 kB
AnonPages:    13900808 kB
Mapped:          20356 kB
Slab:            56868 kB
PageTables:      41972 kB
NFS_Unstable:        0 kB
Bounce:              0 kB
CommitLimit:  83586992 kB
Committed_AS: 35122948 kB
VmallocTotal: 34359738367 kB
VmallocUsed:    296008 kB
VmallocChunk: 34359440975 kB
HugePages_Total:     0
HugePages_Free:      0
HugePages_Rsvd:      0
Hugepagesize:     2048 kB

Free space on /tmp at the end= 72348 MiB
End job on node112 at 2011-05-03 00:13:51