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