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

namespace YukiCoder
{
    class Program
    {
        //--------------------------------------------------------------//
        static int nN;
        static int[] wi;
        //--------------------------------------------------------------//
        static bool xxx( int N, int[]wi)
        {
            int nSum = wi.Sum();
            int nSv2 = nSum / 2;
            if (nSum % 2 == 1) return false;

            bool[] dp = new bool[nSum + 1];
            dp[0] = true;
            for (int i = 0; i < N; i++)
            {
                for (int j = nSv2; j >= 0; j--)
                {
                    if (dp[j])      dp[j + wi[i]] = true;
                }
            }
            return dp[nSv2];
        }
        //--------------------------------------------------------------//
        static void Main(string[] args)
        {
            nN = int.Parse(Console.ReadLine());
            wi = Console.ReadLine().Split().Select(int.Parse).ToArray();
            
            if (xxx(nN, wi))    Console.WriteLine("possible");
            else                Console.WriteLine("impossible");
            //Console.ReadLine();
        }
    }
}