#include<iostream>
#include<cstdio>

using namespace std;

int main ()
{
    int x1,x2,y1,y2;
    double x3,y3;
    scanf("%d%d%lf\n%d%d%lf",&x1,&x2,&x3,&y1,&y2,&y3);
    printf("VALOR A PAGAR: R$ %.2lf",x2*x3+y2*y3);

    return 0;
}