#include <bits/stdc++.h>
using namespace std;
template <typename T>
void get_int(T &x) {
  char t = getchar();
  bool neg = false;
  x = 0;
  for (; (t > '9' || t < '0') && t != '-'; t = getchar())
    ;
  if (t == '-') neg = true, t = getchar();
  for (; t <= '9' && t >= '0'; t = getchar()) x = x * 10 + t - '0';
  if (neg) x = -x;
}
template <typename T>
void print_int(T x) {
  if (x < 0) putchar('-'), x = -x;
  short a[20] = {}, sz = 0;
  while (x > 0) a[sz++] = x % 10, x /= 10;
  if (sz == 0) putchar('0');
  for (int i = sz - 1; i >= 0; i--) putchar('0' + a[i]);
}
const int inf = 0x3f3f3f3f;
const long long Linf = 1ll << 61;
const double pi = acos(-1.0);
int a, b, ww;
double calc(double a1) {
  double a2 = sqrt(1.0 * ww * ww - a1 * a1);
  double dis = (-a1 * a2 + a1 * b + a2 * a) / (1.0 * ww);
  return max(dis, 0.0);
}
int main() {
  get_int(a), get_int(b), get_int(ww);
  double l = 0, r = 1e10, m1, m2;
  for (int i = 1; i <= 1000; i++) {
    m1 = calc((l + l + r) / 3);
    m2 = calc((l + r + r) / 3);
    if (m1 > m2)
      l = (l + l + r) / 3;
    else
      r = (l + r + r) / 3;
  }
  r = calc(r);
  if (ww <= b) r = max(r, a * 1.0);
  if (ww <= a) r = max(r, b * 1.0);
  r = min(r, ww * 1.0);
  if (r < 1e-10)
    puts("My poor head =(");
  else
    printf("%.10lf\n", r);
  return 0;
}
