#include <bits/stdc++.h>
#include <atcoder/all>
using namespace std;
using namespace atcoder;
using ll = long long;
using ld = long double;

int main() {
  int P, Q, R;
  cin >> P >> Q >> R;
  double a = (double)P / (P + Q + R);
  double b = (double)Q / (P + Q + R);
  double c = (double)R / (P + Q + R);
  cout << fixed << setprecision(15) << max({a, b, c, 1 - a, 1 - b, 1 - c}) << endl;
  return 0;
}