using System; using System.IO; using System.Linq; using System.Text; using System.Diagnostics; using System.Collections.Generic; using System.Text.RegularExpressions; using Enu = System.Linq.Enumerable; class Program { static readonly string Possible = "possible", Impossible = "impossible"; void Solve() { int N = reader.Int(); var W = reader.IntArray(N); int Sum = W.Sum(); if (Sum % 2 == 1) { Console.WriteLine(Impossible); return; } int Want = Sum / 2; var dp = new bool[Want + 1]; dp[0] = true; foreach (int w in W) for (int i = Want - w; i >= 0; i--) dp[i + w] |= dp[i]; if (dp[Want]) Console.WriteLine(Possible); else Console.WriteLine(Impossible); } Reader reader = new Reader(Console.In); static void Main() { new Program().Solve(); } } class Reader { private readonly TextReader reader; private readonly char[] separator = { ' ' }; private readonly StringSplitOptions removeOp = StringSplitOptions.RemoveEmptyEntries; private string[] A = new string[0]; private int i; public Reader(TextReader r) { reader = r; } public bool HasNext() { return Enqueue(); } public string String() { return Dequeue(); } public int Int() { return int.Parse(Dequeue()); } public long Long() { return long.Parse(Dequeue()); } public double Double() { return double.Parse(Dequeue()); } public int[] IntLine() { var s = Line(); return s == "" ? new int[0] : Array.ConvertAll(Split(s), int.Parse); } public int[] IntArray(int N) { return Enu.Range(0, N).Select(i => Int()).ToArray(); } public int[][] IntGrid(int H) { return Enu.Range(0, H).Select(i => IntLine()).ToArray(); } public string[] StringArray(int N) { return Enu.Range(0, N).Select(i => Line()).ToArray(); } public string Line() { return reader.ReadLine().Trim(); } private string[] Split(string s) { return s.Split(separator, removeOp); } private bool Enqueue() { if (i < A.Length) return true; string line = reader.ReadLine(); if (line == null) return false; if (line == "") return Enqueue(); A = Split(line); i = 0; return true; } private string Dequeue() { Enqueue(); return A[i++]; } }