#include <iostream>
#include <stdio.h>

using namespace std;

int n;
long double p, q;
long double mat[1005][1005];

void swap(int i, int j)
{
	for(int k = 1; k <= n+1; k++){
		long double t = mat[i][k];
		mat[i][k] = mat[j][k];
		mat[j][k] = t;
	}
}

int main(void)
{
	cin >> n >> p >> q;
	
	for(int i = 1; i <= n; i++){
		for(int j = 1; j <= n; j++){
			if(i==j)  mat[i][j] = 1;
			if(i+1==j) mat[i][j] = -q;
			if(i==j+1) mat[i][j] = -p;
		}
	}
	mat[1][n+1] = p;
	
	for(int i = 1; i <= n; i++){
		long double div = mat[i][i];
		for(int j = i; j <= i+1; j++) if(j <= n) mat[i][j] /= div;
		mat[i][n+1] /= div;
		
		for(int j = 1; j <= i+1; j++){
			if(j+1 > n) continue;
			long double coe = mat[j][i];
			if(i == j) continue;
			for(int k = i; k <= i+1; k++){
				if(k <= n) mat[j][k] -= coe * mat[i][k];
			}
			mat[j][n+1] -= coe * mat[i][n+1];
		}
	}
	
	printf("%.11Lf\n", mat[1][n+1]);
	return 0;
}