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