#include <bits/stdc++.h>
using namespace std;
int main() {
  int n, ans1 = INT_MAX, ans = -198896785;
  cin >> n;
  int c = 0, d = 0;
  for (int i = 0; i < n; i++) {
    int a;
    cin >> a;
    if (a < 0) {
      c++;
      ans = max(a, ans);
    }
    if (a > 0) {
      d++;
      ans1 = min(a, ans1);
    }
  }
  n = (n + 1) / 2;
  if (d >= n)
    cout << ans1 << endl;
  else if (c >= n)
    cout << ans << endl;
  else
    cout << 0 << endl;
  return 0;
}
