ruby, 133 bytes

Result

AC

Duration

615ms

Code [DL]

j,k,l,a,b,c,d,e,f,g,h,i=`dd`.split.map &:to_i
a-=j
b-=k
c-=l
d-=j
e-=k
f-=l
g-=j
h-=k
i-=l
p (a*e*i+b*f*g+c*d*h-a*h*f-b*i*d-c*g*e)/6

stdin

01 21 43
44 50 82
33 91 12
23 89 86

stdout

30866

stderr

0+1 records in
0+1 records out

strace