#include<iostream>
#include<iomanip>
using namespace std;
int N;
double p,q;
main()
{
	cin>>N>>p>>q;
	double now=p;
	for(int i=N-1;i--;)
	{
		now=p+(q<1e-10?0:q*q*now/(1-now*now));
	}
	cout<<fixed<<setprecision(15)<<now<<endl;
}