node, 148 bytes

Result

AC

Duration

585ms

Code [DL]

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

stdin

93 64 64
12 26 09
16 52 65
27 93 89

stdout

20397

stderr

strace