perl, 199 bytes

Result

AC

Duration

541ms

Code [DL]

use Data::Dumper;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

08 43 91
79 63 12
44 13 25
26 68 60

stdout

11330

stderr

strace