main(y,z){int a[z=12];for(;z--;)scanf("%d",a+z);for(;z<9;)a[z]-=a[9+z++%3];printf("%d",(a[3]*a[7]*a[2]+a[6]*a[1]*a[5]+*a*a[4]*a[8]-a[6]*a[4]*a[2]-*a*a[7]*a[5]-a[3]*a[1]*a[8])/6);}