#include<stdio.h>
int main()
{
    int price_x,quantity_x,prize_y,quantity_y,prize_z,quantity_z;
    scanf("%d %d", &price_x,&quantity_x);
    scanf("%d %d", &price_y,&quantity_y);
    scanf("%d %d", &price_z,&quantity_z);
    if(price_x<=0&&quantity_x<=0&&price_y<=0&&quantity_y<=0;prize_z<=0&&quantity_z<=0)
    {
        printf("Invalid input");
    }
    else
    { int Totalcost
      Totalcost=(price_x*quantity_x)+(price_y*quantity_y)+(price_z*quantity_z);
      printf("%d\n",Totalcost);
    }
}