#include <iostream>
#include <cmath>
using namespace std;
int main(){
	cout.precision(20);
	int n;
	double p,q;
	cin >> n >> p >> q;
	if(p==0){
		cout << 0 << endl;
		return 0;
	}
	if(q==0){
		cout << p << endl;
		return 0;
	}
	if(p + q==1){
		cout << 1 - 1/(double)(n + 1) << endl;
		return 0;
	}
	double x = (1 + p*p - q*q)/p;
	long double u = (x + sqrt(x*x - 4))/2,v = (x - sqrt(x*x - 4))/2;
	cout << (pow(u,n) - pow(v,n))/(pow(u,n + 1) - pow(v,n + 1)) << endl;
}