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