#include <bits/stdc++.h>
using namespace std;
int main() {
  int n;
  cin >> n;
  int a[n];
  int pos_mn = 1000;
  int neg_mx = -1000;
  int pos = 0;
  int neg = 0;
  for (int i = 0; i < n; i++) {
    cin >> a[i];
    if (a[i] < 0) {
      ++neg;
      neg_mx = max(neg_mx, a[i]);
    } else if (a[i] > 0) {
      ++pos;
      pos_mn = min(pos_mn, a[i]);
    }
  }
  int need = n / 2;
  if (n & 1) ++need;
  if (pos < need && neg < need) {
    cout << "0" << endl;
    return 0;
  }
  if (pos >= need)
    cout << pos_mn;
  else
    cout << neg_mx;
}
