csharp, 282 bytes

Result

WA

Duration

876ms

Code [DL]

using System;using System.Linq;class A{static void Main(){char[]c={' ','\n'};int[]a=Console.In.ReadToEnd().Split(c).Select(Int32.Parse).ToArray();for(int z=9;z-->0;)a[z]-=a[9+z%3];Console.Write((a[7]*(a[0]*a[5]-a[3]*a[2])+a[6]*(a[4]*a[2]-a[1]*a[5])+a[8]*(a[3]*a[1]-a[0]*a[4]))/6);}}

stdin

44 36 95
40 07 48
04 82 81
77 76 42

stdout

stderr

Unhandled Exception:
System.FormatException: Input string was not in a correct format.
  at System.Number.StringToNumber (System.String str, System.Globalization.NumberStyles options, System.Number+NumberBuffer& number, System.Globalization.NumberFormatInfo info, System.Boolean parseDecimal) [0x00057] in <fb0d2884a2b44d8db375bbed7cc70740>:0 
  at System.Number.ParseInt32 (System.String s, System.Globalization.NumberStyles style, System.Globalization.NumberFormatInfo info) [0x00015] in <fb0d2884a2b44d8db375bbed7cc70740>:0 
  at System.Int32.Parse (System.String s) [0x00007] in <fb0d2884a2b44d8db375bbed7cc70740>:0 
  at System.Linq.Enumerable+SelectArrayIterator`2[TSource,TResult].ToArray () [0x00012] in <fe779a58d2d54ffea553ee896d1fee6a>:0 
  at System.Linq.Enumerable.ToArray[TSource] (System.Collections.Generic.IEnumerable`1[T] source) [0x0001f] in <fe779a58d2d54ffea553ee896d1fee6a>:0 
  at A.Main () [0x00043] in <19faa491c78943a7818376f1a9284301>:0 
[ERROR] FATAL UNHANDLED EXCEPTION: System.FormatException: Input string was not in a correct format.
  at System.Number.StringToNumber (System.String str, System.Globalization.NumberStyles options, System.Number+NumberBuffer& number, System.Globalization.NumberFormatInfo info, System.Boolean parseDecimal) [0x00057] in <fb0d2884a2b44d8db375bbed7cc70740>:0 
  at System.Number.ParseInt32 (System.String s, System.Globalization.NumberStyles style, System.Globalization.NumberFormatInfo info) [0x00015] in <fb0d2884a2b44d8db375bbed7cc70740>:0 
  at System.Int32.Parse (System.String s) [0x00007] in <fb0d2884a2b44d8db375bbed7cc70740>:0 
  at System.Linq.Enumerable+SelectArrayIterator`2[TSource,TResult].ToArray () [0x00012] in <fe779a58d2d54ffea553ee896d1fee6a>:0 
  at System.Linq.Enumerable.ToArray[TSource] (System.Collections.Generic.IEnumerable`1[T] source) [0x0001f] in <fe779a58d2d54ffea553ee896d1fee6a>:0 
  at A.Main () [0x00043] in <19faa491c78943a7818376f1a9284301>:0 

strace