#include <stdio.h>
int main ()
{
    int q1, p1, q2, p2, q3, p3;
    if (scanf("%d %d", &q1, &p1) != 2 ||
        scanf("%d %d", &q2, &p2) != 2 ||
        scanf("%d %d", &q3, &p3) != 2) {
            printf("Invalid input\n");
            return 0;
        }
        if (q1 < 0 || p1 < 0 || q2 < 0 || p2 < 0 || q3 < 0 || p3 < 0)
        printf("Invalid input\n"); 
         } else {
           int total = q1 * p1 + q2 * p2 + q3 * p3;
           printf("%d\n",total);
       }
       return 0;
       }