#include <cmath>
#include <cstdio>
#include <cstdlib>
#include <cstring>

#include <algorithm>
#include <bitset>
#include <complex>
#include <iostream>
#include <map>
#include <numeric>
#include <queue>
#include <set>
#include <stack>
#include <string>
#include <unordered_map>
#include <unordered_set>
#include <vector>

#include <cassert>
#include <functional>

using ll = long long;
using namespace std;

template<typename A, typename B>
bool chmin(A &a, const B b) {
  if (a <= b) return false;
  a = b;
  return true;
}

template<typename A, typename B>
bool chmax(A &a, const B b) {
  if (a >= b) return false;
  a = b;
  return true;
}

#ifndef LOCAL
#define debug(...) ;
#else
#define debug(...) cerr << __LINE__ << " : " << #__VA_ARGS__ << " = " << _tostr(__VA_ARGS__) << endl;

template<typename T>
ostream &operator<<(ostream &out, const vector<T> &v);

template<typename T1, typename T2>
ostream &operator<<(ostream &out, const pair<T1, T2> &p) {
  out << "{" << p.first << ", " << p.second << "}";
  return out;
}

template<typename T>
ostream &operator<<(ostream &out, const vector<T> &v) {
  out << '{';
  for (const T &item : v) out << item << ", ";
  out << "\b\b}";
  return out;
}

void _tostr_rec(ostringstream &oss) {
  oss << "\b\b \b";
}

template<typename Head, typename... Tail>
void _tostr_rec(ostringstream &oss, Head &&head, Tail &&...tail) {
  oss << head << ", ";
  _tostr_rec(oss, forward<Tail>(tail)...);
}

template<typename... T>
string _tostr(T &&...args) {
  ostringstream oss;
  int size = sizeof...(args);
  if (size > 1) oss << "{";
  _tostr_rec(oss, forward<T>(args)...);
  if (size > 1) oss << "}";
  return oss.str();
}
#endif

constexpr int mod = 1'000'000'007; //1e9+7(prime number)
constexpr int INF = 1'000'000'000; //1e9
constexpr ll LLINF = 2'000'000'000'000'000'000LL; //2e18
constexpr int SIZE = 4010;

int dp[SIZE][SIZE][2];

int main() {
  int N, M;
  int A[SIZE];

  scanf("%d%d", &N, &M);

  for (int i = 0; i < N; i++) scanf("%d", A + i);

  sort(A, A + N, greater<int>());

  for (int i = 0; i <= N; i++) {
    for (int j = 0; j <= N; j++) {
      dp[i][j][0] = dp[i][j][1] = -INF;
    }
  }

  dp[0][0][0] = 0;

  for (int i = 0; i < N; i++) {
    for (int j = M; j >= 0; j--) {
      int d = A[i] - A[i + 1];
      int tmp = dp[i][j][0];

      chmax(dp[i][j][0], dp[i][j][1]);
      chmax(dp[i][j][1], tmp + A[i]);
      chmax(dp[i + 1][j][0], dp[i][j][0]);
      if (j + d <= M)
        chmax(dp[i + 1][j + d][1], dp[i][j][1]);
    }
  }

  int ans = -INF;

  for (int i = 0; i <= M; i++) {
    chmax(ans, dp[N - 1][i][0]);
  }

  cout << ans << endl;

  return 0;
}