n, k = map(int, input().split())
a = list(map(int, input().split()))

a = sorted(a, reverse=True)
ans = 0
cnt = 0
for i in range(k):
    if a[i] > 0:
        ans += a[i]
        cnt += 1

if cnt == 0:
    ans += a[0]
print(ans)