#include <bits/stdc++.h>
using namespace std;
double b;
double dg(int a)
{
	if(a==1)
	{
		return b/(1+b);
	}
	return b/(a+dg(a-1));
 } 
int main()
{
	int a;
	cin>>a>>b; 
    cout<<fixed<<setprecision(2)<<dg(a);
    return 0;
}

1

2

0.67