#include<bits/stdc++.h>
using namespace std;
int main()
{
	int n,d,s,x,y;
	scanf("%d %d %d %d %d",&n,&d,&s,&x,&y);
	double ans=1.0*s/d/n*1.0*x*y;
	printf("%.3lf",ans);
	return 0;
}