#include <bits/stdc++.h>
using namespace std;
double a, b, l;
double pi = acos((double)-1);
inline double solve() {
  if (a > b) swap(a, b);
  if (l <= a)
    return l;
  else if (l <= b)
    return a;
  else {
    double th = atan(cbrt(a / b));
    double maxl = b / cos(th) + a / sin(th);
    if (l > maxl + 1e-7) return -1000;
    double ll = 0, rr = pi / 2;
    for (int k = 0; k < 50; k++) {
      double mm = (ll + rr) / 2;
      double d = -a * sin(mm) + b * cos(mm) - l * cos(2 * mm);
      if (d < 0)
        ll = mm;
      else
        rr = mm;
    }
    return a * cos(ll) + b * sin(ll) - l * sin(2 * ll) / 2;
  }
}
int main() {
  scanf("%lf%lf%lf", &a, &b, &l);
  double t = solve();
  if (t >= 0)
    printf("%.7lf\n", solve());
  else
    puts("My poor head =(");
}
