#include <bits/stdc++.h>
//#include <atcoder/all>
using namespace std;
//using namespace atcoder;
//using mint = modint1000000007;
//const int mod = 1000000007;
//using mint = modint998244353;
//const int mod = 998244353;
//const int INF = 1e9;
//const long long LINF = 1e18;
#define rep(i, n) for (int i = 0; i < (n); ++i)
#define rep2(i,l,r)for(int i=(l);i<(r);++i)
#define rrep(i, n) for (int i = (n-1); i >= 0; --i)
#define rrep2(i,l,r)for(int i=(r-1);i>=(l);--i)
#define all(x) (x).begin(),(x).end()
#define allR(x) (x).rbegin(),(x).rend()
#define endl "\n"
#define P pair<double,double>
template<typename A, typename B> inline bool chmax(A & a, const B & b) { if (a < b) { a = b; return true; } return false; }
template<typename A, typename B> inline bool chmin(A & a, const B & b) { if (a > b) { a = b; return true; } return false; }
P f(P l, P r) {
	double resl = l.first + (r.first * l.second * l.second) / (1.0 - l.first*r.first);
	double resr = l.second * r.second / (1.0 - l.first*r.first);
	return { resl,resr };
}
int main() {
	ios::sync_with_stdio(false);
	cin.tie(nullptr);
	int n; cin >> n;
	P pq; cin >> pq.first >> pq.second;
	P ans = { 0,1 };
	while (n) {
		if (1 == n % 2) ans = f(ans, pq);
		pq = f(pq, pq);
		n /= 2;
	}
	printf("%.16f\n", ans.first);
	return 0;
}