#include <bits/stdc++.h>
using namespace std;
template <class T>
using max_pq = priority_queue<T>;
template <class T>
using min_pq = priority_queue<T, vector<T>, greater<T>>;
long long int x, y;
template <class T>
T gcd(T a, T b) {
  if (a == 0) {
    x = 0, y = 1;
    return b;
  }
  T gc = gcd(b % a, a);
  T temp;
  temp = x;
  x = y - (b / a) * temp;
  y = temp;
  return gc;
}
long long int po(long long int a, long long int x, long long int m) {
  if (x == 0) {
    return 1;
  }
  long long int ans = 1;
  long long int k = 1;
  while (k <= x) {
    if (x & k) {
      ans = ((ans * a) % m);
    }
    k <<= 1;
    a *= a;
    a %= m;
  }
  return ans;
}
int a, b, l;
bool check(double w) {
  for (double ang = 0.0000; ang <= 3.1415926535898 / 2.0; ang += 0.000005) {
    double i = b - w * cos(ang);
    i /= sin(ang);
    double j = a - w * sin(ang);
    j /= cos(ang);
    if (l * cos(ang) + w * sin(ang) <= a) return true;
    if (i + j < l && j > 0 && i > 0) return false;
  }
  return true;
}
int main() {
  ios::sync_with_stdio(false);
  cout.tie(0);
  cin.tie(0);
  cin >> a >> b >> l;
  if (l <= b) {
    cout << min(l, a) << '\n';
    return 0;
  }
  double low = 0, high = min(l, b);
  high = min(high, (double)a);
  double ans = 0;
  while (high - low > 1e-8) {
    double mid = low + high;
    mid /= 2;
    if (check(mid)) {
      ans = mid;
      low = mid + 1e-8;
    } else
      high = mid - 1e-8;
  }
  if (ans == 0)
    cout << "My poor head =(";
  else
    printf("%.8lf", ans);
}
