#include <bits/stdc++.h>
using namespace std;
double a, b, l;
double calc(double x) { return (a - (l * cos(x) - b) * tan(x)) * cos(x); }
int main() {
  scanf("%lf%lf%lf", &a, &b, &l);
  if (a > b) swap(a, b);
  if (l <= a)
    printf("%.7lf\n", l);
  else if (l > a && l <= b)
    printf("%.7lf\n", a);
  else {
    double L = 0, R = acos(0);
    for (int i = 1; i <= 100; ++i) {
      double ml = L + (R - L) / 3.0, mr = R - (R - L) / 3.0;
      calc(ml) < calc(mr) ? R = mr : L = ml;
    }
    calc(L) < 1e-13 ? puts("My poor head =(") : printf("%.7lf\n", calc(L));
  }
  return 0;
}
