#include<stdio.h>
int main()
{
    int qx,qy,qz;
    int px,py,pz;
    long long total;
    scanf("%d %d",&qx,&px);
    scanf("%d %d",&qy,&py);
    scanf("%d %d",&qz,&pz);
    if(qx<0||qy<0||qz<0||px<0||py<0||pz<0){
        printf("Invalid input\n");
        return 0;
    }
    total=(long long)qx*px + (long long)qy*py +(long long)qz*pz;
    printf("%11d\n",total);
    return 0;
}