using System;
using static System.Console;
using System.Linq;
using System.Collections.Generic;

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, m) = (c[0], c[1]);
        var a = NList;
        if (m % 2 == 1)
        {
            WriteLine(0);
            return;
        }
        var set = new HashSet<int>(a);
        var ans = 0L;
        foreach (var ai in a) if (ai <= m / 2 && set.Contains(ai + m / 2)) ans += n - 2;
        WriteLine(ans); 
    }
}