node, 170 bytes

Result

AC

Duration

576ms

Code [DL]

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

stdin

05 87 69
97 98 88
38 14 55
73 64 14

stdout

71524

stderr

strace