#include <iostream>
#include <algorithm>
#include <iomanip>
#include <vector>
#include <queue>
#include <set>
#include <map>
#include <tuple>
#include <cmath>
#include <numeric>
#include <functional>
#include <cassert>

#define debug_value(x) cerr << "line" << __LINE__ << ":<" << __func__ << ">:" << #x << "=" << x << endl;
#define debug(x) cerr << "line" << __LINE__ << ":<" << __func__ << ">:" << x << endl;

template<class T> inline bool chmax(T& a, T b) { if (a < b) { a = b; return 1; } return 0; }
template<class T> inline bool chmin(T& a, T b) { if (a > b) { a = b; return 1; } return 0; }

using namespace std;
typedef long long ll;

int main(){
    ios::sync_with_stdio(false);
    cin.tie(0);
    cout << setprecision(10) << fixed;
    int n;
    double p, q;
    cin >> n >> p >> q;
    vector<double> p0(n+1), p1(n+1);
    vector<double> p0_pre(n+1), p1_pre(n+1);
    p0[1] = 1;
    auto ok = [&](){
        auto p = accumulate(p0.begin(), p0.end(), 0.0)+accumulate(p1.begin(), p1.end(), 0.0);
        // cout << p << endl;
        return p < 0.0009;
    };
    double ans = 0.0;
    while(!ok()){
        swap(p0, p0_pre);
        swap(p1, p1_pre);
        p0[0] = 0; p0[n] = 0;
        p1[0] = 0; p1[n] = 0;
        ans += p0_pre[1]*p+p1_pre[1]*q;
        for(int i = 1; i <= n-1; i++){
            p0[i] = p0_pre[i-1]*q+p1_pre[i-1]*p;
            p1[i] = p0_pre[i+1]*p+p1_pre[i+1]*q;
        }
    }
    cout << ans << endl;
}