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