#include <bits/stdc++.h>
using namespace std;

double solve(int N, double p, double q){
    if (p == 1){
        return 1;
    }else if (p == 0){
        return 0;
    }else if (q == 1){
        return 0;
    }else if (q == 0){
        return p;
    }
    vector<double> f(N + 2, 0.0);
    vector<double> b(N + 2, 0.0);
    vector<double> new_f(N + 2, 0.0);
    vector<double> new_b(N + 2, 0.0);
    f[1] = 1.0;
    double precision = 0.0001;
    double dead = 0;
    double returned = 0;
    double finished = 0;
    double alive = 1.0;
    double r = 1.0 - p - q;
    while (alive > returned * precision){
        new_f.assign(N + 2, 0.0);
        new_b.assign(N + 2, 0.0);
        for (int i = 1; i <= N; ++i){
            new_b[i - 1] += p * f[i] + q * b[i];
            new_f[i + 1] += q * f[i] + p * b[i];
            dead += r * f[i] + r * b[i];
        }
        returned += new_b[0];
        finished += new_f[N + 1];
        alive = 1.0 - dead - returned - finished;
        swap(f, new_f);
        swap(b, new_b);
    }
    return returned;
}

int main()
{
    ios::sync_with_stdio(false);
    cout.tie(0);
    int N;
    double p, q;
    cin >> N >> p >> q;
    cout << fixed << setprecision(15) << solve(N, p, q) << endl;
    return 0;
}