r = lambda: map(int, raw_input().split())
n, m = r()
if m<2:
    print 0
    exit(0)
w = r()
INF = 10**9
rm = range(m)
rm1 = range(m+1)
def solve(b):
    dp = r_dp; rs = r_rs
    ret = -INF
    for i in xrange(1,n-1):
        wi = w[i-1]
        dp2 = [-INF] + [max(dp[j]+wi, rs[j]) for j in rm]
        for j in rm1:
            rs[j] = max(dp[j], rs[j])
        dp = dp2
        ret = max(ret, dp[m])
    wi = w[-2]
    dp2 = [-INF] + [max(dp[j]+wi, rs[j])+b for j in rm]
    return max(ret, dp2[m])

r_dp = [-INF]*(m+1); r_rs = [-INF]*(m+1)
r_dp[1] = 0
rr = solve(w[-1])
r_dp = [-INF]*(m+1); r_rs = [-INF]*(m+1)
r_rs[0] = 0
print max(rr, solve(0))