#include <iostream>
#include <cstdio>

using namespace std;
int main()
{
    int number1, x1, number2,x2;
    double total;
    double y1,y2;
    cin >> number1 >> x1 >> y1;
    cin >> number2 >> x2 >> y2;
    total = x1 * y1 + x2 * y2;
    printf("VALOR A PAGAR: R$ %.2lf",total);

    return 0;
}