using System;using System.Linq;class A{static void Main(){char[]c={' ','\n'};string s=Console.In.ReadToEnd();int[]a=s.Split(c).Take(12).Select(Int32.Parse).ToArray();int s=0,1=0;for(int z=8;z-->0;)a[z%9]-=a[9+z%3],s+=a[z%3]*=a[p=3+(z+1)%3]*a[q=6+(z+2)%3]-a[q-3]*a[p+3];Console.Write(s/6);}}