n, m = map(int, input().split())
w = list(map(int, input().split()))
dp = [[[[-10**18]*2 for _ in range(m+1)] for _ in range(2)] for _ in range(2)]
dp[0][0][0][0] = 0
dp[0][1][1][1] = 0

for i in range(n-1):
    for j in range(2):
        for k in range(m+1):
            for l in range(2):
                dp[(i+1)&1][j][k][l] = -10**18
                
    for j in range(m+1):
        for k in range(2):
            dp[(i+1)&1][0][j][k] = max(dp[i&1][0][j][k], dp[i&1][1][j][k])
            
            if j+1<=m:
                dp[(i+1)&1][1][j+1][k] = max(dp[i&1][0][j][k], dp[i&1][1][j][k]+w[i])+(w[-1] if i==n-2 and k==1 else 0)

ans = -10**18

for i in range(2):
    for j in range(2):
        ans = max(ans, dp[(n-1)&1][i][m][j])

print(ans)