#include <bits/stdc++.h>
using namespace std;
double f(double x, double A, double B, double L) {
  double y = sqrt(L * L - x * x);
  return (A * x + B * y - x * y) / L;
}
int main(void) {
  double A, B, L;
  scanf("%lf%lf%lf", &A, &B, &L);
  if (L <= B) {
    printf("%.8f\n", min(A, L));
    return 0;
  } else if (L <= A) {
    printf("%.8f\n", min(B, L));
    return 0;
  } else {
    double left = 0.0, right = L, ma, mb;
    for (int u = 0; u < 500; u++) {
      ma = (left * 3 + right) / 4.0;
      mb = (left + right * 3) / 4.0;
      double fa = f(ma, A, B, L);
      double fb = f(mb, A, B, L);
      if (fa < fb)
        right = mb;
      else
        left = ma;
    }
    double ff = f((left + right) / 2.0, A, B, L);
    ff = min(ff, L);
    ff = min(ff, A);
    if (ff < 1e-8)
      printf("My poor head =(\n");
    else
      printf("%.8f\n", ff);
  }
  return 0;
}
