Trace number 3284776

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
UmSat 2011-02-25Signal 10.4414 10.4461

General information on the benchmark

Nameapplication/rintanen/SATPlanning/
sokoban-sequential-p145-microban-sequential.070-NOTKNOWN.cnf
MD5SUMf52ec4dacdcf65c3aedb61fb46ade01b
Bench CategoryAPPLICATION (applications instances)
Best result obtained on this benchmarkSAT
Best CPU time to get the best result obtained on this benchmark1119.56
Satisfiable
(Un)Satisfiability was proved
Number of variables153284
Number of clauses2473656
Sum of the clauses size5647736
Maximum clause length78
Minimum clause length1
Number of clauses of size 1696
Number of clauses of size 22387280
Number of clauses of size 36720
Number of clauses of size 431080
Number of clauses of size 513440
Number of clauses of size over 534440

Solver Data


Verifier Data 

ERROR: Unexpected answer ! (SATISFIABLE/UNSATISFIABLE expected)
Got answer: <no 's ' line found>

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-3284776-1303761076/watcher-3284776-1303761076 -o /tmp/evaluation-result-3284776-1303761076/solver-3284776-1303761076 -C 2400 -W 1300 -M 7680 umsat HOME/instance-3284776-1303761076.cnf 

running on 2 cores: 4,6

Enforcing CPUTime limit (soft limit, will send SIGTERM then SIGKILL): 2400 seconds
Enforcing CPUTime limit (hard limit, will send SIGXCPU): 2430 seconds
Enforcing wall clock limit (soft limit, will send SIGTERM then SIGKILL): 1300 seconds
Enforcing VSIZE limit (soft limit, will send SIGTERM then SIGKILL): 7864320 KiB
Enforcing VSIZE limit (hard limit, stack expansion will fail with SIGSEGV, brk() and mmap() will return ENOMEM): 7915520 KiB
Current StackSize limit: 10240 KiB


[startup+0 s]
/proc/loadavg: 4.17 4.05 3.99 5/189 4792
/proc/meminfo: memFree=14640836/32950928 swapFree=67111528/67111528
[pid=4792] ppid=4790 vsize=11644 CPUtime=0 cores=4,6
/proc/4792/stat : 4792 (umsat) R 4790 4792 4254 0 -1 4194304 346 0 0 0 0 0 0 0 23 0 1 0 487706571 11923456 285 33554432000 4194304 4263880 140736658493104 18446744073709551615 268272349893 0 0 4096 0 0 0 0 17 4 0 0 0
/proc/4792/statm: 2911 285 240 17 0 84 0

[startup+0.0109419 s]
/proc/loadavg: 4.17 4.05 3.99 5/189 4792
/proc/meminfo: memFree=14640836/32950928 swapFree=67111528/67111528
[pid=4792] ppid=4790 vsize=11776 CPUtime=0 cores=4,6
/proc/4792/stat : 4792 (umsat) R 4790 4792 4254 0 -1 4194304 371 0 0 0 0 0 0 0 23 0 1 0 487706571 12058624 310 33554432000 4194304 4263880 140736658493104 18446744073709551615 47669020703469 0 0 4096 0 0 0 0 17 4 0 0 0
/proc/4792/statm: 2944 310 240 17 0 117 0
Current children cumulated CPU time (s) 0
Current children cumulated vsize (KiB) 11776

[startup+0.101042 s]
/proc/loadavg: 4.17 4.05 3.99 5/189 4792
/proc/meminfo: memFree=14640836/32950928 swapFree=67111528/67111528
[pid=4792] ppid=4790 vsize=13472 CPUtime=0.09 cores=4,6
/proc/4792/stat : 4792 (umsat) R 4790 4792 4254 0 -1 4194304 903 0 0 0 9 0 0 0 23 0 1 0 487706571 13795328 696 33554432000 4194304 4263880 140736658493104 18446744073709551615 4203264 0 0 4096 0 0 0 0 17 4 0 0 0
/proc/4792/statm: 3368 696 242 17 0 541 0
Current children cumulated CPU time (s) 0.09
Current children cumulated vsize (KiB) 13472

[startup+0.300953 s]
/proc/loadavg: 4.17 4.05 3.99 5/189 4792
/proc/meminfo: memFree=14640836/32950928 swapFree=67111528/67111528
[pid=4792] ppid=4790 vsize=18812 CPUtime=0.29 cores=4,6
/proc/4792/stat : 4792 (umsat) R 4790 4792 4254 0 -1 4194304 2556 0 0 0 29 0 0 0 25 0 1 0 487706571 19263488 1771 33554432000 4194304 4263880 140736658493104 18446744073709551615 47669020738465 0 0 4096 0 0 0 0 17 4 0 0 0
/proc/4792/statm: 4703 1771 242 17 0 1876 0
Current children cumulated CPU time (s) 0.29
Current children cumulated vsize (KiB) 18812

[startup+0.700879 s]
/proc/loadavg: 4.17 4.05 3.99 5/189 4792
/proc/meminfo: memFree=14640836/32950928 swapFree=67111528/67111528
[pid=4792] ppid=4790 vsize=26108 CPUtime=0.69 cores=4,6
/proc/4792/stat : 4792 (umsat) R 4790 4792 4254 0 -1 4194304 4974 0 0 0 69 0 0 0 25 0 1 0 487706571 26734592 3420 33554432000 4194304 4263880 140736658493104 18446744073709551615 47669020964212 0 0 4096 0 0 0 0 17 4 0 0 0
/proc/4792/statm: 6527 3421 242 17 0 3700 0
Current children cumulated CPU time (s) 0.69
Current children cumulated vsize (KiB) 26108

[startup+1.50074 s]
/proc/loadavg: 4.17 4.05 3.99 6/190 4793
/proc/meminfo: memFree=14623708/32950928 swapFree=67111528/67111528
[pid=4792] ppid=4790 vsize=40700 CPUtime=1.49 cores=4,6
/proc/4792/stat : 4792 (umsat) R 4790 4792 4254 0 -1 4194304 9785 0 0 0 148 1 0 0 25 0 1 0 487706571 41676800 6694 33554432000 4194304 4263880 140736658493104 18446744073709551615 4232288 0 0 4096 0 0 0 0 17 4 0 0 0
/proc/4792/statm: 10175 6694 242 17 0 7348 0
Current children cumulated CPU time (s) 1.49
Current children cumulated vsize (KiB) 40700

[startup+3.1004 s]
/proc/loadavg: 4.17 4.05 3.99 6/190 4793
/proc/meminfo: memFree=14583036/32950928 swapFree=67111528/67111528
[pid=4792] ppid=4790 vsize=69752 CPUtime=3.09 cores=4,6
/proc/4792/stat : 4792 (umsat) R 4790 4792 4254 0 -1 4194304 19359 0 0 0 306 3 0 0 25 0 1 0 487706571 71426048 13195 33554432000 4194304 4263880 140736658493104 18446744073709551615 47669020703478 0 0 4096 0 0 0 0 17 4 0 0 0
/proc/4792/statm: 17438 13195 242 17 0 14611 0
Current children cumulated CPU time (s) 3.09
Current children cumulated vsize (KiB) 69752

[startup+6.30089 s]
/proc/loadavg: 4.24 4.06 4.00 5/190 4793
/proc/meminfo: memFree=14533832/32950928 swapFree=67111528/67111528
[pid=4792] ppid=4790 vsize=127856 CPUtime=6.28 cores=4,6
/proc/4792/stat : 4792 (umsat) R 4790 4792 4254 0 -1 4194304 38537 0 0 0 623 5 0 0 25 0 1 0 487706571 130924544 26228 33554432000 4194304 4263880 140736658493104 18446744073709551615 268272688896 0 0 4096 0 0 0 0 17 4 0 0 0
/proc/4792/statm: 31964 26228 242 17 0 29137 0
Current children cumulated CPU time (s) 6.28
Current children cumulated vsize (KiB) 127856

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

[startup+7.90061 s]
/proc/loadavg: 4.24 4.06 4.00 6/190 4793
/proc/meminfo: memFree=14517960/32950928 swapFree=67111528/67111528
[pid=4792] ppid=4790 vsize=127856 CPUtime=7.89 cores=4,6
/proc/4792/stat : 4792 (umsat) R 4790 4792 4254 0 -1 4194304 40857 0 0 0 783 6 0 0 25 0 1 0 487706571 130924544 28548 33554432000 4194304 4263880 140736658493104 18446744073709551615 47669020738353 0 0 4096 0 0 0 0 17 4 0 0 0
/proc/4792/statm: 31964 28548 242 17 0 29137 0
Current children cumulated CPU time (s) 7.89
Current children cumulated vsize (KiB) 127856

[startup+9.50026 s]
/proc/loadavg: 4.24 4.06 4.00 5/190 4793
/proc/meminfo: memFree=14443568/32950928 swapFree=67111528/67111528
[pid=4792] ppid=4790 vsize=244064 CPUtime=9.49 cores=4,6
/proc/4792/stat : 4792 (umsat) R 4790 4792 4254 0 -1 4194304 71931 0 0 0 939 10 0 0 25 0 1 0 487706571 249921536 47333 33554432000 4194304 4263880 140736658493104 18446744073709551615 268272375488 0 0 4096 0 0 0 0 17 4 0 0 0
/proc/4792/statm: 61016 47333 242 17 0 58189 0
Current children cumulated CPU time (s) 9.49
Current children cumulated vsize (KiB) 244064

[startup+9.90718 s]
/proc/loadavg: 4.22 4.06 4.00 5/190 4793
/proc/meminfo: memFree=14436748/32950928 swapFree=67111528/67111528
[pid=4792] ppid=4790 vsize=244064 CPUtime=9.89 cores=4,6
/proc/4792/stat : 4792 (umsat) R 4790 4792 4254 0 -1 4194304 72514 0 0 0 979 10 0 0 25 0 1 0 487706571 249921536 47916 33554432000 4194304 4263880 140736658493104 18446744073709551615 4236897 0 0 4096 0 0 0 0 17 4 0 0 0
/proc/4792/statm: 61016 47916 242 17 0 58189 0
Current children cumulated CPU time (s) 9.89
Current children cumulated vsize (KiB) 244064

[startup+10.3001 s]
/proc/loadavg: 4.22 4.06 4.00 5/190 4793
/proc/meminfo: memFree=14436748/32950928 swapFree=67111528/67111528
[pid=4792] ppid=4790 vsize=244064 CPUtime=10.28 cores=4,6
/proc/4792/stat : 4792 (umsat) R 4790 4792 4254 0 -1 4204032 72921 0 0 0 1006 22 0 0 25 0 1 0 487706571 249921536 48323 33554432000 4194304 4263880 140736658493104 18446744073709551615 4204973 0 0 4096 0 0 0 0 17 4 0 0 0
/proc/4792/statm: 61016 48323 244 17 0 58189 0
Current children cumulated CPU time (s) 10.28
Current children cumulated vsize (KiB) 244064

[startup+10.4001 s]
/proc/loadavg: 4.22 4.06 4.00 5/190 4793
/proc/meminfo: memFree=14436748/32950928 swapFree=67111528/67111528
[pid=4792] ppid=4790 vsize=244064 CPUtime=10.38 cores=4,6
/proc/4792/stat : 4792 (umsat) R 4790 4792 4254 0 -1 4204032 72921 0 0 0 1006 32 0 0 25 0 1 0 487706571 249921536 48323 33554432000 4194304 4263880 140736658493104 18446744073709551615 4204973 0 0 4096 0 0 0 0 17 4 0 0 0
/proc/4792/statm: 61016 48323 244 17 0 58189 0
Current children cumulated CPU time (s) 10.38
Current children cumulated vsize (KiB) 244064

Child ended because it received signal 11 (SIGSEGV)
Child dumped core
Real time (s): 10.4461
CPU time (s): 10.4414
CPU user time (s): 10.0665
CPU system time (s): 0.374943
CPU usage (%): 99.9552
Max. virtual memory (cumulated for all children) (KiB): 293220

getrusage(RUSAGE_CHILDREN,...) data:
user time used= 10.0665
system time used= 0.374943
maximum resident set size= 0
integral shared memory size= 0
integral unshared data size= 0
integral unshared stack size= 0
page reclaims= 72921
page faults= 0
swaps= 0
block input operations= 0
block output operations= 0
messages sent= 0
messages received= 0
signals received= 0
voluntary context switches= 4
involuntary context switches= 16

runsolver used 0.018997 second user time and 0.041993 second system time

The end

Launcher Data 

Begin job on node122 at 2011-04-25 21:51:18
IDJOB=3284776
IDBENCH=82363
IDSOLVER=1582
FILE ID=node122/3284776-1303761076
RUNJOBID= node122-1303759508-4273
PBS_JOBID= 13157134
Free space on /tmp= 70832 MiB

SOLVER NAME= UmSat 2011-02-25
BENCH NAME= SAT11/application/rintanen/SATPlanning/sokoban-sequential-p145-microban-sequential.070-NOTKNOWN.cnf
COMMAND LINE= umsat BENCHNAME
RUNSOLVER COMMAND LINE= BIN/runsolver --timestamp -w /tmp/evaluation-result-3284776-1303761076/watcher-3284776-1303761076 -o /tmp/evaluation-result-3284776-1303761076/solver-3284776-1303761076 -C 2400 -W 1300 -M 7680  umsat HOME/instance-3284776-1303761076.cnf

TIME LIMIT= 2400 seconds
MEMORY LIMIT= 7680 MiB
NBCORE= 2

MD5SUM BENCH= f52ec4dacdcf65c3aedb61fb46ade01b
RANDOM SEED=127305133

node122.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		: 2666.820
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	: 5333.64
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		: 2666.820
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	: 5332.75
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		: 2666.820
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	: 5332.75
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		: 2666.820
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	: 5332.83
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		: 2666.820
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	: 5332.75
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		: 2666.820
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	: 5332.75
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		: 2666.820
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	: 5332.75
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		: 2666.820
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	: 5332.97
clflush size	: 64
cache_alignment	: 64
address sizes	: 40 bits physical, 48 bits virtual
power management: [8]


/proc/meminfo:
MemTotal:     32950928 kB
MemFree:      14640992 kB
Buffers:       1784120 kB
Cached:       15220216 kB
SwapCached:          0 kB
Active:        6809732 kB
Inactive:     10944196 kB
HighTotal:           0 kB
HighFree:            0 kB
LowTotal:     32950928 kB
LowFree:      14640992 kB
SwapTotal:    67111528 kB
SwapFree:     67111528 kB
Dirty:           46020 kB
Writeback:           0 kB
AnonPages:      749472 kB
Mapped:          15528 kB
Slab:           491704 kB
PageTables:       6656 kB
NFS_Unstable:        0 kB
Bounce:              0 kB
CommitLimit:  83586992 kB
Committed_AS:   954616 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= 70640 MiB
End job on node122 at 2011-04-25 21:51:28