using System; using System.Collections.Generic; using System.Linq; static public class Program { static public void Main() { var n = readInteger().Validate(x => 1 <= x && x <= (int)1e5); var a = readInteger(n).ValidateArray(x => 1 <= x && x <= (int)1e9); var ok = new bool[n]; for (int i = 0; i < n; i++) ok[i] = true; for (int i = 0; i < n; i++) { if (!ok[i]) continue; for (int j = i + 1; j < n; j++) { if (a[i] == a[j]) { ok[i] = ok[j] = false; } } } Console.WriteLine(ok.Count(x => x)); } static int readInteger() { var s = Console.ReadLine(); return int.Parse(s); } static int[] readInteger(int n, params char[] sep) { var s = Console.ReadLine().Split(sep); if (s.Length != n) throw new Exception(string.Format("invalid input, expected{0} actual{1}", n, s.Length)); var ret = new int[n]; for (int i = 0; i < n; i++) ret[i] = int.Parse(s[i]); return ret; } static void readEOF() { if (Console.In.Peek() >= 0) throw new Exception("invalid input too long input file"); } } static public class Ex { static public T Validate(this T input, Func f) { if (!f(input)) throw new Exception("invalid input"); return input; } static public T[] ValidateArray(this T[] input, Func f) { foreach (var x in input) if (!f(x)) throw new Exception("invalid input"); return input; } }