lua, 220 bytes

Result

WA

Duration

483ms

Code [DL]

for k=1,4 do for s in string.gmatch(io.read(),"[^%s]+")do a[#a+1]=s end end
for z=0,8 do a[z+1]=a[z+1]-a[10+z%3]end
print(math.floor(-(a[8]*(a[4]*a[3]-a[1]*a[6])+a[7]*(a[2]*a[6]-a[5]*a[3])+a[9]*(a[1]*a[5]-a[4]*a[2]))/6))

stdin

95 13 09
28 19 26
80 31 96
94 83 63

stdout

stderr

/usr/bin/lua5.3: /volume/CODE:1: attempt to get length of a nil value (global 'a')
stack traceback:
	/volume/CODE:1: in main chunk
	[C]: in ?

strace