#include <bits/stdc++.h>
using namespace std;
int d, v1, v2;
int main() {
  cin >> d >> v1 >> v2;
  int v3 = v1 + v2;
  double t = d * 1.0 / v3;
  double ans = 1.0 * v1 * t;
  cout << fixed;
  cout << setprecision(10) << ans;
  return 0;
}
