#include <bits/stdc++.h>
using namespace std;
int main() {
  int n, pn = 0, nn = 0;
  int pa = 1e9, tmp;
  int na = -1e9;
  cin >> n;
  for (int i = 0; i < n; ++i) {
    cin >> tmp;
    if (tmp > 0) {
      ++pn;
      pa = min(pa, tmp);
    } else if (tmp < 0) {
      ++nn;
      na = max(na, tmp);
    }
  }
  n = (n + 1) / 2;
  if (pn >= n) {
    cout << pa << endl;
  } else if (nn >= n) {
    cout << na << endl;
  } else
    cout << 0 << endl;
  return 0;
}
