using System; using static System.Console; using System.Linq; using System.Collections.Generic; using System.Diagnostics; class Program { static int NN => int.Parse(ReadLine()); static int[] NList => ReadLine().Split().Select(int.Parse).ToArray(); static int[][] NArr(long n) => Enumerable.Repeat(0, (int)n).Select(_ => NList).ToArray(); public static void Main() { Solve(); } static void Solve() { var c = NList; var (n, x) = (c[0], c[1]); var a = NList; var dic = new Dictionary(); var ans = 0L; for (var i = 0; i < n; ++i) { if (dic.ContainsKey(x - a[i])) ans += dic[x - a[i]] * 2; if (a[i] * 2 == x) ++ans; if (dic.ContainsKey(a[i])) ++dic[a[i]]; else dic[a[i]] = 1; } WriteLine(ans); } }