N,M = map(int,input().split())
A = list(map(int,input().split()))
A.sort(reverse = True)

import sys
if N == 2:
    d = A[0] - A[1]
    if d <= M:
        print(A[0])
    else:
        print(0)
    exit()
    
inf = 10 ** 10
dp = [[0] * (M+1) for _ in range(N-1)]
if A[0] - A[1] <= M:
    dp[0][A[0]-A[1]] = A[0]
if A[1] - A[2] <= M:
    dp[1][A[1]-A[2]] = A[1]
for i in range(1,N-1):
    d = A[i] - A[i+1]
    for j in range(M+1):
        dp[i][j] = dp[i-1][j]
    if i == 1:
        if d <= M:
            dp[i][d] = max(dp[i][d],A[i])
        continue
    for j in range(M+1):
        if j + d <= M:
            dp[i][j+d] = max(dp[i][j+d],dp[i-2][j] + A[i])
        else:
            break
_max = 0
for j in range(M+1):
    if dp[-1][j] > _max:
        _max = dp[-1][j]
    if dp[-2][j] > _max:
        _max = dp[-2][j]
print(_max)