#include <bits/stdc++.h>
using namespace std;
#define int long long
#define rep(i, a, b) for (int i = (int)(a); i < (int)(b); ++i)
template <class T>
bool chmax(T &a, const T& b) {
    if (a < b) {
        a = b;
        return true;
    }
    return false;
}
template <class T>
bool chmin(T &a, const T& b) {
    if (a > b) {
        a = b;
        return true;
    }
    return false;
}

constexpr int INF = 1e9;
constexpr double EPS = 1e-5;


long double N, p, q;
long double ans;
void rec(int i, int dir, long double P) {
    if (P < EPS || i == N) return;
    if (i == 0) {
        ans += P;
        return;
    }
    rec(i + (dir ? 1 : -1), dir, P * q);
    rec(i + ((dir ^ 1) ? 1 : -1), dir ^ 1, P * p);
}
signed main() {
    cin >> N >> p >> q;
    rec(1, 1, 1);
    cout << ans << endl;
}