#include <iostream>
#include <iomanip>
using namespace std;

int N;
long double p,q;
long double dp[1010][1010][2];

int main(){
    cin >> N >> p >> q;
    dp[0][1][0] = 1;
    for(int i=0;i<=1000;i++){
        for(int j=1;j<N;j++){
            dp[i+1][j+1][0] += dp[i][j][0]*q;
            dp[i+1][j-1][1] += dp[i][j][0]*p;
        }
        for(int j=1;j<N;j++){
            dp[i+1][j-1][1] += dp[i][j][1]*q;
            dp[i+1][j+1][0] += dp[i][j][1]*p;
        }
    }
    long double ans = 0;
    for(int i=1;i<=1000;i++) ans += dp[i][0][1];
    cout << fixed;
    cout << setprecision(10) << ans << endl;
}