d-dmd, 196 bytes

Result

WA

Duration

1230ms

Code [DL]

import std.stdio;void main(){int[30]a;for(int i=0;readf("%d",&a[i]);i++)a[i]-=a[i%3]*(i>2);printf("%d\n",(a[3]*(a[7]*a[11]-a[8]*a[10])+a[4]*(a[8]*a[9]-a[11]*a[6])+a[5]*(a[10]*a[6]-a[7]*a[9]))/6);}

stdin

05 02 84
12 92 21
42 76 71
93 49 41

stdout

stderr

std.conv.ConvException@/usr/include/dmd/phobos/std/conv.d(2253): Unexpected ' ' when converting from type LockingTextReader to type int
----------------
??:? int std.conv.parse!(int, std.stdio.LockingTextReader).parse(ref std.stdio.LockingTextReader) [0x43cabf]
??:? int std.conv.parse!(int, std.stdio.LockingTextReader).parse(ref std.stdio.LockingTextReader, uint) [0x43c7be]
??:? int std.format.unformatValueImpl!(int, std.stdio.LockingTextReader, char).unformatValueImpl(ref std.stdio.LockingTextReader, ref const(std.format.FormatSpec!(char).FormatSpec)) [0x43c07e]
??:? int std.format.unformatValue!(int, std.stdio.LockingTextReader, char).unformatValue(ref std.stdio.LockingTextReader, ref const(std.format.FormatSpec!(char).FormatSpec)) [0x43bf84]
??:? uint std.format.formattedRead!(std.stdio.LockingTextReader, char, int*).formattedRead(ref std.stdio.LockingTextReader, const(char)[], ref int*) [0x438bac]
??:? uint std.stdio.File.readf!(int*).readf(const(char[]), ref int*) [0x438afb]
??:? uint std.stdio.readf!(int*).readf(const(char[]), int*) [0x438a58]
??:? _Dmain [0x438949]

strace