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

if(scanf("%d %d" ,&qz, &pz) !=2) 

    printf("Invalide input");
    return 0;
}
if(qx < 0 || px < 0 || qy < 0 || py < || qz < 0 || pz < 0)
{
    printf("Invalide input");
    return 0;
}

total = (qx * px) + (qy * py) + (qz * pz);
printf("%ld", total);
retuen 0;
}