n,m = map(int,input().split())
*a, = map(int,input().split())
a.sort(reverse=1)
ans = 0
dp = [[0]*(m+1) for _ in range(n+1)]
for i in range(n+1):
    D = dp[i]
    if i+1 <= n:
        for j in range(m+1):
            dp[i+1][j] = max(dp[i+1][j],D[j])
    if i+2 <= n:
        v = a[i]-a[i+1]
        for j in range(m+1-v):
            dp[i+2][j+v] = max(dp[i+2][j+v],D[j]+a[i])
    if i+3 <= n:
        v = a[i]-a[i+2]
        for j in range(m+1-v):
            dp[i+3][j+v] = max(dp[i+3][j+v],D[j]+a[i])
print(max(dp[-1]))