n,m = map(int,raw_input().split())
w = map(int,raw_input().split())
if m == 0:
	print 0
	quit()
if m == n:
	print sum(w)
	quit()
def solve(start):
	dp = {(m-start,start):0}
	for i in xrange(n-1):
		tmp_dp = dict()
		for (k,h),v in dp.iteritems():
			for nxt in xrange(2):
				if 0 <= k-nxt < n-1-i:
					nk = (k-nxt,nxt)
					nv =  v + (w[i] if h*nxt == 1 else 0)
					if nk not in tmp_dp or tmp_dp[nk] < nv:
						tmp_dp[nk] = nv
		dp = tmp_dp
	return max(v + (w[n-1] if h*start else 0) for (k,h),v in dp.iteritems())
print max(solve(0), solve(1))