## https://yukicoder.me/problems/no/1522

def main():
    N, M = map(int, input().split())
    A = list(map(int, input().split()))

    A.sort(reverse=True)
    dp = [[0] * (M + 1 ) for _ in range(N)]
    for i in range(1, N):
        
        for m in range(M + 1):
            a = A[i - 1]
            b = A[i - 1] - A[i]
            
            # 選ばない場合
            dp[i][m] = max(dp[i][m], dp[i - 1][m])

            # 選ぶ場合
            if m + b <= M:
                dp[i][m + b] = max(dp[i][m + b], dp[i - 2][m] + a)

    answer = 0
    for m in range(M + 1):
        answer = max(answer, dp[-1][m])
    print(answer)







if __name__ == '__main__':
    main()