#include <bits/stdc++.h>
using namespace std;
const double eps = 1e-8;
double a, b, L;
double calc(double x) {
  return fabs(a * x + sqrt(L * L - x * x) * (b - x)) / L;
}
int main() {
  scanf("%lf%lf%lf", &a, &b, &L);
  if (a > b) swap(a, b);
  double l = 0;
  double r = L;
  double midl, midr;
  while (l + eps < r) {
    midl = l + (r - l) / 3;
    midr = r - (r - l) / 3;
    if (fabs(calc(midl)) < fabs(calc(midr))) {
      r = midr;
    } else
      l = midl;
  }
  double ans = calc(l);
  if (L >= a && L <= b) {
    printf("%.7f\n", a);
  } else if (L <= a) {
    printf("%.7f\n", L);
  } else if (ans < eps)
    printf("My poor head =(\n");
  else
    printf("%.7f\n", ans);
  return 0;
}
