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();
    public static void Main()
    {
        Solve();
    }
    static void Solve()
    {
        var c = NList;
        var (n, m) = (c[0], c[1]);
        var a = NList;
        Array.Sort(a, (l, r) => r.CompareTo(l));
        var INF = long.MinValue;
        var dp = new long[n][];
        for (var i = 0; i < n; ++i) dp[i] = Enumerable.Repeat(INF, m + 1).ToArray();
        for (var i = 0; i < n; ++i)
        {
            if (i > 0)
            {
                for (var j = 0; j <= m; ++j) dp[i][j] = dp[i - 1][j];
            }
            if (i == 0) dp[i][0] = 0;
            else if (i == 1)
            {
                if (a[i - 1] - a[i] <= m) dp[i][a[i - 1] - a[i]] = a[i - 1];
            }
            else if (i > 1)
            {
                for (var j = 0; j <= m; ++j)
                {
                    if (j + a[i - 1] - a[i] > m) break;
                    dp[i][j + a[i - 1] - a[i]] = Math.Max(dp[i][j + a[i - 1] - a[i]], dp[i - 2][j] + a[i - 1]);
                }
            }
        }
        WriteLine(dp[^1].Max());
    }
}