z=12;a[12];s,q;main(p){for(;z--;z<9&&(a[z]-=a[9+z%3]),z<3&&(s+=a[z]*=a[p=3+-~z%3]*a[q=6+(z+2)%3]-a[q-3]*a[p+3]))scanf("%d",a+z);printf("%d",s/6);}