#include <bits/stdc++.h> using namespace std; int n, a[1005], f[1000005]; int main() { cin >> n; for (int i = 1; i <= n; i++) { cin >> a[i]; } sort(a + 1, a + 1 + n); for (int i = n; i > 0; i--) { bool flag = false; for (int j = -1000; j <= 1000; j++) { flag = flag || a[i] == 1ll * j * j; } if (!flag) { cout << a[i] << endl; exit(0); } } return 0; }