#include <iostream>
#include <iomanip>

using ldouble = long double;

using pdouble = std::pair<ldouble, ldouble>;

pdouble merge(pdouble a, pdouble b) {
    if (a.first == 1) return pdouble(1, 0);

    return pdouble(a.first + a.second * a.second * b.first / (1 - a.first * b.first),
                   a.second * b.second / (1 - a.first * b.first));
}

void solve() {
    int n;
    ldouble p, q;
    std::cin >> n >> p >> q;

    pdouble base(p, q);
    auto ans = base;
    --n;

    while (n--) ans = merge(ans, base);

    std::cout << std::fixed << std::setprecision(20)
              << ans.first << "\n";
}

int main() {
    std::cin.tie(nullptr);
    std::ios::sync_with_stdio(false);

    solve();

    return 0;
}