perl, 173 bytes

Result

AC

Duration

528ms

Code [DL]

my($a,$b,$c,$d,$e,$f,$g,$h,$i,$j,$k,$l)=map{split' '}<>;$e-=$b;$f-=$c;$h-=$b;$i-=$c;$k-=$b;$l-=$c;print+(($g-$a)*($k*$f-$e*$l)+($j-$a)*($e*$i-$h*$f)+($d-$a)*($h*$l-$k*$i))/6

stdin

97 05 52
47 29 60
02 13 96
31 61 79

stdout

10988

stderr

strace