#include <bits/stdc++.h>
using namespace std;
#define rep(i,n) for (int i = 0; i < (n); ++i)
#define Inf 1000000000


int main(){
	
	int N;
	cin>>N;
	double p,q;
	cin>>p>>q;
	
	vector dp(N,vector<double>(2,0.0));
	dp[0][0] = 1.0;
	
	double ans = 0.0;
	
	rep(_,20000){
		vector ndp(N,vector<double>(2,0.0));
		
		rep(i,N){
			if(i!=0){
				ndp[i-1][1] += dp[i][0]*p;
				ndp[i-1][1] += dp[i][1]*q;
			}
			else{
				ans += dp[i][0]*p;
				ans += dp[i][1]*q;
			}
			if(i!=N-1){
				ndp[i+1][0] += dp[i][0]*q;
				ndp[i+1][1] += dp[i][1]*p;
			}
		}
		
		swap(dp,ndp);
		
	}
	
	cout<<fixed<<setprecision(10)<<ans<<endl;
	
	return 0;
}