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