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

# Generate pairs of adjacent elements and their values
pairs = []
for i in range(len(A) - 1):
    pairs.append((A[i] - A[i+1], A[i]))

max_k = len(pairs)
max_possible_k = min(max_k, n // 2)

# Initialize DP table
dp = [[-1] * (M + 1) for _ in range(max_possible_k + 1)]
dp[0][0] = 0

for (d, v) in pairs:
    # Update DP in reverse to avoid overwriting current state
    for j in range(max_possible_k, 0, -1):
        for m in range(M, d - 1, -1):
            if dp[j-1][m - d] != -1:
                if dp[j][m] < dp[j-1][m - d] + v:
                    dp[j][m] = dp[j-1][m - d] + v

# Find the maximum possible O
max_O = 0
for k in range(0, max_possible_k + 1):
    for m in range(0, M + 1):
        if dp[k][m] != -1:
            max_O = max(max_O, dp[k][m])

print(max_O)