#include <bits/stdc++.h>
using namespace std;
int a, b, l;
double f(double x) { return cos(x) * (b * tan(x) - l * sin(x) + a); }
int main() {
  double L, R, lm, rm, w;
  scanf("%d%d%d", &a, &b, &l);
  if (a > b) swap(a, b);
  if (l <= b)
    w = min(l, a);
  else {
    L = 0, R = acos(0);
    for (int i = 0; i < 120; i++) {
      lm = (L + L + R) / 3, rm = (L + R + R) / 3;
      if (f(lm) > f(rm))
        L = lm;
      else
        R = rm;
    }
    w = f(L);
  }
  if (w >= 1e-7)
    printf("%.7lf\n", w);
  else
    cout << "My poor head =(" << endl;
  return 0;
}
