#define _USE_MATH_DEFINES
#include <cstdio>
#include <iostream>
#include <sstream>
#include <fstream>
#include <iomanip>
#include <algorithm>
#include <cmath>
#include <complex>
#include <string>
#include <vector>
#include <array>
#include <list>
#include <queue>
#include <stack>
#include <set>
#include <map>
#include <bitset>
#include <numeric>
#include <limits>
#include <climits>
#include <cfloat>
#include <functional>
#include <iterator>
#include <memory>
#include <regex>
using namespace std;

const int RIGHT = 0;
const int LEFT  = 1;

int main()
{
    int n;
    double p, q;
    cin >> n >> p >> q;

    vector<vector<double> > dp(2, vector<double>(n+2, 0.0));
    dp[RIGHT][1] = 1.0;
    double ans = 0.0;
    for(int i=0; i<30000; ++i){
        vector<vector<double> > nextDp(2, vector<double>(n+2, 0.0));
        for(int j=1; j<=n; ++j){
            nextDp[LEFT][j-1]  += dp[RIGHT][j] * p;
            nextDp[RIGHT][j+1] += dp[LEFT][j]  * p;
            nextDp[RIGHT][j+1] += dp[RIGHT][j] * q;
            nextDp[LEFT][j-1]  += dp[LEFT][j]  * q;
        }
        dp = move(nextDp);
        ans += dp[LEFT][0];
    }

    double rest = 0.0;
    for(int j=1; j<=n; ++j)
        rest += dp[RIGHT][j] + dp[LEFT][j];
    ans /= 1.0 - rest;

    cout.setf(ios_base::fixed, ios_base::floatfield);
    cout << setprecision(10) << ans << endl;

    return 0;
}