#include <bits/stdc++.h>
using namespace std;
const double pi = acos(-1);
const double eps = 1e-7;
int a, b, l;
double f(double ang) {
  double x = l * sin(ang);
  double y = l * cos(ang);
  complex<double> p(b, a);
  complex<double> v1(x, -y);
  complex<double> v2(b, a - y);
  double cross = x * (a - y) - (b * (-y));
  double dis = cross / abs(v1);
  double s = cross / abs(v1) / abs(v2);
  return dis;
}
double ts() {
  double lo = 0;
  double hi = pi / 2;
  for (int i = 0; i < 500; i++) {
    double m1 = (lo * 2 + hi) / 3;
    double m2 = (lo + 2 * hi) / 3;
    if (f(m1) < f(m2))
      hi = m2;
    else
      lo = m1;
  }
  return f(lo);
}
int main() {
  scanf("%d %d %d", &a, &b, &l);
  double mn = ts();
  mn = min(mn, 1.0 * l);
  if (l <= b || l <= a) {
    printf("%d\n", min(min(a, b), l));
  } else if (mn < eps)
    printf("My poor head =(\n");
  else
    printf("%.10lf\n", mn);
}
