#include <bits/stdc++.h>

using namespace std;

using ll = long long;

int main() {
	cin.tie(0);
	ios::sync_with_stdio(false);
	int n;
	cin >> n;
	long double p, q;
	cin >> p >> q;
	q += p;

	int seed = 0;
	mt19937 mt(seed);
	uniform_real_distribution<long double> rnd(0, 1);
	int cnt = 0;
	const int LOOP_NUM = 50000;
	for (int i = 0; i < LOOP_NUM; i++) {
		int cur = 1;
		int d = 1;
		while (true) {
			long double val = rnd(mt);
			if (val <= p) {
				d = -d;
				cur += d;
			} else if (val <= q) {
				cur += d;
			} else {
				break;
			}
			if (cur == n + 1) break;
			if (cur == 0) {
				cnt++;
				break;
			}
		}
	}
	cout << fixed << setprecision(15) << (double)cnt / LOOP_NUM << endl;
	return 0;
}