#include <bits/stdc++.h>
using namespace std;
double a, b, l;
double eps = 1e-8;
double func(double x) {
  return (x * a + sqrt(l * l - x * x) * b - sqrt(l * l - x * x) * x) / l;
}
double tsearch(double l, double r) {
  if (r - l < eps) return (l + r) / 2;
  double a = (2 * l + r) / 3;
  double b = (l + 2 * r) / 3;
  if (func(a) < func(b)) return tsearch(l, b);
  return tsearch(a, r);
}
void solve() {
  cin >> a >> b >> l;
  if (l <= b) {
    printf("%.9lf", min(a, l));
    return;
  }
  if (l <= a) {
    printf("%.9lf", min(b, l));
    return;
  }
  double ans = func(tsearch(0, l));
  if (ans < eps)
    printf("My poor head =(\n");
  else
    printf("%.9lf\n", min(ans, l));
}
int main() {
  solve();
  return 0;
}
