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

public class Program
{
    public static void Main() {
        string[] d = Console.ReadLine().Split(' ');
        int N = int.Parse(d[0]);
        var da = Console.ReadLine().Split(' ').Select(x => int.Parse(x)).ToArray();

        if (da.Sum(x => x) % 2 != 0) {
            Console.WriteLine("impossible");
            return;
        }

        int m = da.Sum(x => x) / 2;

        var dp = new bool[10000];
        dp[0] = true;

        for (int i = 0; i < N; i++) {
            for (int j = m; j >= da[i]; j--) {
                dp[j] |= dp[j - da[i]];
            }
        }

        if (dp[m]) {
            Console.WriteLine("possible");
        }
        else {
            Console.WriteLine("impossible");
        }
    }
}