#include<stdio.h>
/*#define MIN_QUANTITY -10000
#define MAX_QUANTITY 10000
#define MIN_PRICE -1000
#define MAX_PRICE 1000*/
int main()
{
    int quantityX,priceX,quantityY,priceY,quantityZ,priceZ;
    long int Totalcost;
    scanf("%d %d",&quantityX, &priceX);
    scanf("%d %d",&quantityY, &priceY);
    scanf("%d %d",&quantityZ, &priceZ);
    Totalcost=((quantityX*priceX)+(quantityY*priceY)+(quantityZ*priceZ));
    if((quantityX>=-10^4&&quantityY>=-10^4&&quantityZ>=-10^4)&&(priceX>=-10^3&&priceY>=-10^3&&priceZ>=-10^3))
    printf("Invalid input);
    else
    printf("%ld",Totalcost);
    return 0;
}