using System;
using System.Linq;
using System.IO;
using System.Text;
using System.Collections;
using System.Collections.Generic;

/**
 * Auto-generated code below aims at helping you parse
 * the standard input according to the problem statement.
 **/
class Solution
{
    static void Main(string[] args)
    {
        int n = int.Parse(Console.ReadLine()); // the number of temperatures to analyse
        string[] inputs = Console.ReadLine().Split(' ');
        if (n == 0) {
            Console.WriteLine(0);
            return;
        }
        int positive = 5527;
        int negative = -274;
        for (int i = 0; i < n; i++)
        {
            int t = int.Parse(inputs[i]); // a temperature expressed as an integer ranging from -273 to 5526
            if (t == 0) {
                Console.WriteLine(0);
                return;
            }
            if (t > 0 && t < positive)
                positive = t;
            else if (t < 0 && t > negative)
                negative = t;
        }

        Console.WriteLine ((positive.CompareTo (Math.Abs (negative))) < 1 ? positive : negative);
    }
}