perl, 182 bytes

Result

AC

Duration

528ms

Code [DL]

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

stdin

62 75 86
54 31 03
32 29 84
19 67 38

stdout

31049

stderr

strace