using System; using System.Collections.Generic; using System.Linq; namespace yukicoder { public class Program { public static void Main() { var n = int.Parse(Console.ReadLine()); var w = Console.ReadLine().Split(' ').Select(x => int.Parse(x)).ToArray(); var k = w.Sum(); var c = new bool[n, k / 2 + 1]; c[0, 0] = true; c[0, w[0]] = true; if (k % 2 != 0) { Console.WriteLine("impossible"); } else { for (var i = 1; i < n; i++) { for(var j = 0; j <= k / 2 ; j++) { if (c[i - 1, j]) { c[i, j] = true; if (j + w[i] <= k / 2) { c[i, j + w[i]] = true; } } } } if (c[n - 1, k / 2]) { Console.WriteLine("possible"); } else { Console.WriteLine("impossible"); } } } } }