#include #define rep(i,a,b) for(int i=a;i=b;i--) #define fore(i,a) for(auto &i:a) #define all(x) (x).begin(),(x).end() //#pragma GCC optimize ("-O3") using namespace std; void _main(); int main() { cin.tie(0); ios::sync_with_stdio(false); _main(); } typedef long long ll; const int inf = INT_MAX / 2; const ll infl = 1LL << 60; templatebool chmax(T& a, const T& b) { if (a < b) { a = b; return 1; } return 0; } templatebool chmin(T& a, const T& b) { if (b < a) { a = b; return 1; } return 0; } //--------------------------------------------------------------------------------------------------- /*---------------------------------------------------------------------------------------------------             ∧_∧       ∧_∧  (´<_` )  Welcome to My Coding Space!      ( ´_ゝ`) /  ⌒i     /   \    | |     /   / ̄ ̄ ̄ ̄/  |   __(__ニつ/  _/ .| .|____      \/____/ (u ⊃ ---------------------------------------------------------------------------------------------------*/ int N; double P, Q; //--------------------------------------------------------------------------------------------------- void _main() { cin >> N >> P >> Q; if (P == 1) { printf("1\n"); return; } double p = P, q = Q; rep(i, 0, N - 1) { double p1 = p, p2 = P; double q1 = q, q2 = Q; p = p1 + q1 * q1 * p2 / (1.0 - p1 * p2); q = q1 * q2 / (1.0 - p1 * p2); } printf("%.10f\n", p); }