#include"bits/stdc++.h"

using namespace std;
using ll = long long;
using ld = long double;
using pii = pair<int, int>;
using pll = pair<ll, ll>;

#define FOR(k,m,n) for(ll (k)=(m);(k)<(n);(k)++)
#define REP(i,n) FOR((i),0,(n))
#define WAITING(str) int str;std::cin>>str;
#define DEBUGING(str) cout<< #str << " " str<<endl

constexpr int INF = (1 << 30);
constexpr ll INFL = (1ll << 60);
constexpr ll MOD = 1000000007;// 10^9+7

int N;
ld p, q, dead;
vector<ld> nowv, nextv;

using namespace chrono;
int main()
{
	auto start = system_clock::now();

	cin >> N >> p >> q;
	nowv = vector<ld>(N + 2);
	nextv = vector<ld>(N + 2);
	nowv[1] = 1;

	REP(i, 1e9) {
		fill(nextv.begin(), nextv.end(), 0);
		FOR(j, 1, N) {
			nextv[j - 1] += p * nowv[j];
			nextv[j + 1] += q * nowv[j];
			dead += (1 - p - q)*nowv[j];
		}

		FOR(j, 1, N + 1)nowv[j] = nextv[j];
		nowv[0] += nextv[0];
		nowv[N + 1] += nextv[N + 1];
		if (i % 1000 == 0) {
			auto now = system_clock::now();
			auto dur = duration_cast<milliseconds>(now - start).count();
			//cerr << dur << endl;
			if (dur > 1800) {
				break;
			}
		}
	}
	cout << nowv.front();
	//cout << "back: " << nowv.front() << "  go:" << nowv.back() << "  dead:" << dead << endl;

	return 0;
}