#include <bits/stdc++.h>
using namespace std;
#define rep(i,n) for(int i=0;i<(int)n;i++)

int main(){
	int n;
	long double p,q;
	cin >> n >> p >> q;
	vector<long double> dp(2*n+2);
	dp[1] = 1.0;
	rep(zzz,10000){
		vector<long double> dp2(2*n+2);
		rep(i,2*n+1){
			if(i==0){dp2[i] += dp[i];continue;}
			if(i%2==1){
				dp2[i-1] += p*dp[i];
				dp2[i+2] += q*dp[i];
			}else{
				dp2[i+1] += p*dp[i];
				dp2[i-2] += q*dp[i];
			}
		}
		dp = dp2;
	}
	cout.precision(10);
	cout << dp[0] << endl;
	return 0;
}