using System;
using System.Collections.Generic;

class Progaram
{
    static void Main()
    {

        int total = 0;
        int kazu = int.Parse(Console.ReadLine());
        string[] values = Console.ReadLine().Split(' ');
        List<int> list = new List<int>();

        for(int i = 0;i<values.Length;i++){
            list.Add(int.Parse(values[i]));
            total += int.Parse(values[i]);
        }

        list.Sort();

        int x = 0;
        int y = 0;

        foreach(int i in list){
            if(total / 2 >= x){
                x += i;
            }
            else{
                y += i;
            }
        }

        if(x == y){
            Console.WriteLine("possible");
        }
        else{
            Console.WriteLine("impossible");
        }   



    }
}