#include<stdio.h>
int main()
{
    int qx,px,qy,py,qz,pz;
    long long total;
    if (scanf("%d %d",&qx,&px)!=2);
    if (scanf("%d %d",&qy,&py)!=2);
    if (scanf("%d %d",&qz,&pz)!=2);
    if(qx<0||px<0||qy<0||py<0||qz<0||pz<0)
    {
        printf("Invalid input")
    }
    else
    {
        total=(long long)qx*px+(long long)qy*py+(long long)qz*pz;
        printf("%lld",total)
    }
}