#include <bits/stdc++.h>
using namespace std;
const double EPS = 1e-9;
double a, b, len;
double judge(double x) {
  return (b * sqrt(len * len - x * x) + a * x - x * sqrt(len * len - x * x)) /
         len;
}
double ternary(double l, double r) {
  if (fabs(l - r) < EPS) return l;
  double L = l + (r - l) / 3;
  double R = r - (r - l) / 3;
  if (judge(L) < judge(R)) return ternary(l, R);
  return ternary(L, r);
}
void solve() {
  scanf("%lf%lf%lf", &a, &b, &len);
  if (len <= min(a, b)) {
    printf("%.8lf\n", len);
    return;
  }
  if (len <= max(a, b)) {
    printf("%.8lf\n", min(a, b));
    return;
  }
  double ans = judge(ternary(0, len));
  if (ans > 0)
    printf("%.8lf\n", ans);
  else
    printf("My poor head =(\n");
}
int main() {
  solve();
  return 0;
}
