#include "bits/stdc++.h"

using namespace std;

void solve()
{
	int n;
	cin >> n;
	double p, q;
	cin >> p >> q;
	double np = p, nq = q;
	for (int i = 0; i < n - 1; i++)
	{
		np += nq * nq * p / (1 - np * p);
		nq *= q / (1 - np * p);
	}
	cout << fixed << setprecision(9) << np << endl;
}

int main()
{
	solve();
	//cout << "yui(*-v・)yui" << endl;
	return 0;
}