#include<stdio.h>
int main(){
    int q1, p1, q2, p2, q3, p3;
    if (scanf("%d %d %d %d %d", &q1, &p1, &q2, &p2, &q3, &p3) != 6) {
        printf("Invalid input\n");
    }else if (q1 < 0 || p1 < 0 || q2 < 0 || p2 < 0 || q3 , 0 || p3 < 0){
        printf("Invalid input\n");
    } else {
        long long total = (long long)q1 * p1 + (long long)q2 * p2 + (long long)
        q3 * p3;
        printf("%11d\n", total);
    }
    return 0;
}