#include <bits/stdc++.h>
using namespace std;
long double a, b, l;
long double f(long double ang) {
  return a * sinl(ang) + b * cosl(ang) - l * sinl(ang) * cosl(ang);
}
int main() {
  cin >> a >> b >> l;
  long double r1 = 0;
  long double r2 = acosl(0);
  for (int _n(1000), i(0); i < _n; i++) {
    long double r11 = (r1 * 2 + r2) / 3;
    long double r22 = (r1 + r2 * 2) / 3;
    if (f(r11) > f(r22))
      r1 = r11;
    else
      r2 = r22;
  }
  long double res = f(r1);
  if (l <= b) res = max(res, a);
  if (l <= a) res = max(res, b);
  if (res < -1e-9)
    cout << "My poor head =(" << endl;
  else {
    if (res < 1e-9) res = 0;
    res = min(res, l);
    printf("%.8lf\n", (double)res);
  }
  return 0;
}
