n, k = map(int, input().split())
a = list(map(int, input().split()))
reverse_a = sorted(a, reverse=True)

changed_index = 0
for i in range(n):
    if reverse_a[i] > 0:
        changed_index += 1

if k > changed_index:
    print(sum(reverse_a[:changed_index]))
elif k == changed_index:
    print(sum(reverse_a[:k]))