#include<stdio.h>
int main() {
    int qA, pA, qB, pB, qC, pC;
    scanf("%d %d %d %d %d %d", &qA, &pA, &qB, &pB, &qC, &pC);
    if (qA < 0 || pA < 0 || qB < 0 || pB < 0 || qC < 0 || pC < 0) {
        prntf("Invalid input\n");
    } else{
        printf("%d\n", (qA * pA) + (qB * pB) + (qC * pC));
    }
    return 0;
}