#include<iostream>
#include<string>
#include<cstdio>
#include<vector>
#include<cmath>
#include<algorithm>
#include<functional>
#include<iomanip>
#include<queue>
#include<ciso646>
#include<random>
#include<map>
#include<set>
#include<complex>
#include<bitset>
#include<stack>
#include<unordered_map>
#include<utility>
using namespace std;
typedef long long ll;
typedef unsigned long long ul;
typedef unsigned int ui;
typedef long double ld;
typedef pair<int, int> P;
typedef pair<ll, ll> LP;
typedef pair<ld, ld> LDP;
typedef complex<ld> Point;
const ll mod = 1000000007;
const ll INF = mod*mod;
const ld eps = 1e-8;
const ld pi = acos(-1.0);
#define stop char nyaa;cin>>nyaa;
#define rep(i,n) for(int i=0;i<n;i++)
#define per(i,n) for(int i=n-1;i>=0;i--)
#define Rep(i,sta,n) for(int i=sta;i<n;i++)
#define rep1(i,n) for(int i=1;i<=n;i++)
#define per1(i,n) for(int i=n;i>=1;i--)
#define Rep1(i,sta,n) for(int i=sta;i<=n;i++)

ld dp[1001][2],cop[1001][2];
void solve() {
	cout << fixed << setprecision(4);
	int n; cin >> n;
	ld p, q; cin >> p >> q;
	dp[0][0] = 1;
	ld ans = 0;
	rep(aa, 1000) {
		rep(i, n) {
			if(i>0)cop[i][0] = q * dp[i - 1][0] + p * dp[i][1];
			cop[i][1] = q * dp[i + 1][1] + p * dp[i][0];
		}
		rep(i, n) {
			rep(j, 2) {
				dp[i][j] = cop[i][j];
			}
		}
		ans += dp[0][0] + dp[0][1];
		dp[0][0] = dp[0][1] = 0;
	}
	cout << ans << endl;
}
int main() {
	cin.tie(0);
	ios::sync_with_stdio(false);
	solve();
	//stop
	return 0;
}