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

ans = 0
count = 0
for i in range(k):
    if a[i] > 0:
        ans += a[i]
        count += 1

if count == 0:
    print(a[0])
else:
    print(ans)