#include <bits/stdc++.h>
using namespace std;
double a, b, l;
double Func(double x) {
  double y = sqrt(l * l - x * x);
  return fabs(a * y + b * x - x * y) / l;
}
double Solve(double left, double right) {
  while (right - left > 1e-10) {
    double d = (right - left) / 3;
    double k1 = left + d, k2 = right - d;
    double f1 = Func(k1), f2 = Func(k2);
    if (f1 > f2)
      left = k1;
    else
      right = k2;
  }
  return Func(left);
}
int main() {
  while (scanf("%lf%lf%lf", &a, &b, &l) != EOF) {
    if (a > b) swap(a, b);
    if (l <= a)
      printf("%.8lf\n", l);
    else if (l <= b)
      printf("%.8lf\n", a);
    else {
      double ret = Solve(0, l);
      if (ret < 1e-7)
        printf("My poor head =(\n");
      else
        printf("%.8lf\n", ret);
    }
  }
  return 0;
}
