node, 151 bytes

Result

WA

Duration

568ms

Code [DL]

let[,,,a,b,c,d,e,f,g,h,i]=(""+require("fs").readFileSync(0)).split(/\s/).map((e,i,a)=>e|0-a[i%3])
console.log((a*e*i+b*f*g+c*d*h-a*f*h-b*d*i-c*e*g)/6)

stdin

44 81 66
16 79 04
18 18 17
40 68 79

stdout

2015

stderr

strace