#include<stdio.h>
int main(){
    int quantity_x, price_x;
    int quantity_y, price_y;
    int quantity_z, price_z;
    
    scanf("%d %d",&quantity_x,&price_x);
    scanf("%d %d",&quantity_y,&price_y);
    scanf("%d %d",&quantity_z,&price_z);
    
    if(quantity_x<0||price_x<0||quantity_y<0||price_y<0||quantity_z<0||price_z<0){
      printf("Invalid input\n");
     
    }
    else{
        long long total_cost=(long long)quantity_x*price_x*(long long)quantity_y*price_y
        Printf("%lld\n", total_cost);
    } 
    return 0;
}