n,k = map(int,input().split())
ls = list(map(int,input().split()))
s = 0
t = 0
u = -100
for i in range(len(ls)):
	if ls[i] < 0:
		u = max(u,ls[i])
		ls[i] = 0
	else:
		t += 1
ls.sort(reverse=True)
if t != 0:
    print(sum(ls[:k]))
else:
	print(u)