#include <stdio.h>
int main() {
    int quantityX, priceX;
    int quantityY, priceY;
    int quantityZ, priceZ;
    long long totalCost;
    scanf("%d %d", &quantityX, &priceX);
    scanf("%d %d", &quantityY, &priceY);
    scanf("%d %d", &quantityZ, &priceZ);
    totalCost = (long long)quantityX * priceX + (long long)quantityY * priceY + (long long)quantityZ * priceZ;
    printf("%11d\n", totalCost);
    return 0;
}