#include <bits/stdc++.h>
using namespace std;
#ifdef LOCAL
  #include "settings/debug.cpp"
#else
  #define Debug(...) void(0)
#endif
#define rep(i, n) for (int i = 0; i < (n); ++i)
using ll = long long;
using ull = unsigned long long;

int main() {
  int p, q, r;
  cin >> p >> q >> r;
  double s = p + q + r;
  double x = p / s, y = q / s, z = r / s;
  cout << fixed << setprecision(15) << max({ x, y, z, 1 - x, 1 - y, 1 - z }) << endl;
  return 0;
}