package com.javarush.task.task05.task0532;

import java.io.*;

/*
Задача по алгоритмам
*/
import java.util.Scanner;

public class Solution {
    public static void main(String[] args) throws Exception {
           Scanner in = new Scanner(System.in);
        int maximum = 0;
        int min = 0;



       int N = in.nextInt();
       for(int i = 0; i<N; i++)
       {
           int a = in.nextInt();
           if(a>0) {
            if(a>maximum)
            {
               maximum=a;
            }
           }
            if(a<0)
            {
                if(a<min)
                {
                    min=a;

                }
            }
       }
     if((min*(-1))>maximum){
        System.out.println(min);}
     else   {
     System.out.println(maximum);}
    }
}