n,m = map(int,input().split())
w = list(map(int,input().split()))

inf = -10 ** 8
"""
dp1 = [[[inf] * 2 for _ in range(m+1)] for _ in range(n)]
dp1[0][1][1] = 0
dp2 = [[[inf] * 2 for _ in range(m+1)] for _ in range(n)]
dp2[0][0][0] = 0
for i in range(n-1):
    for j in range(m+1):
        dp1[i+1][j][0] = max(dp1[i][j][0],dp1[i][j][1])
        dp2[i+1][j][0] = max(dp2[i][j][0],dp2[i][j][1])
        if j > 0:
            dp1[i+1][j][1] = max(dp1[i][j-1][1] + w[i],dp1[i][j-1][0])
            dp2[i+1][j][1] = max(dp2[i][j-1][1] + w[i],dp2[i][j-1][0])
                             
dp1[-1][m][1] += w[-1]
ans = max(dp1[-1][m][1],dp1[-1][m][0],dp2[-1][m][0],dp2[-1][m][1])
print(ans)
"""
dp1 = [[inf] * 2 for _ in range(m+1)]
dp2 = [[inf] * 2 for _ in range(m+1)]
dp1[1][1] = 0
dp2[0][0] = 0
for i in range(n-1):
    n1 = [[inf] * 2 for _ in range(m+1)]
    n2 = [[inf] * 2 for _ in range(m+1)]
    for j in range(m+1):
        n1[j][0] = max(dp1[j][0],dp1[j][1])
        n2[j][0] = max(dp2[j][0],dp2[j][1])
        if j > 0:
            n1[j][1] = max(dp1[j-1][1] + w[i],dp1[j-1][0])
            n2[j][1] = max(dp2[j-1][1] + w[i],dp2[j-1][0])
    dp1 = n1
    dp2 = n2
dp1[m][1] += w[-1]
ans = max(dp1[m][0],dp1[m][1],dp2[m][0],dp2[m][1])
print(ans)