#include <bits/stdc++.h>
using namespace std;
const double pi = 3.14159265358979323846264338;
double a, b, len, tmp;
double f(double x) { return a * cos(x) + b * sin(x) - 0.5 * len * sin(2 * x); }
double ff(double x) { return -a * sin(x) + b * cos(x) - len * cos(2 * x); }
double aabs(double x) { return x > 0 ? x : -x; }
double get() {
  double l = 0, r = pi / 2.0, m;
  while (aabs(l - r) > 1E-10) {
    m = (l + r) / 2.0;
    if (ff(m) * ff(l) <= 0.0)
      r = m;
    else
      l = m;
  }
  return l;
}
int main() {
  scanf("%lf%lf%lf", &a, &b, &len);
  if (a > b) swap(a, b);
  if (len <= a)
    printf("%.7f\n", len);
  else if (len <= b)
    printf("%.7f\n", a);
  else {
    tmp = f(get());
    if (tmp <= 0)
      puts("My poor head =(");
    else
      printf("%.7f\n", tmp);
  }
  return 0;
}
