n,k=map(int,input().split())
l=[int(i)for i in input().split()]
if int(max(l))<0:
    print(max(l))
else:
    l=[i for i in l if i>-1]
    l.sort(reverse=1>0)
    a=sum(l if len(l)<k else l[:k])
    print(a)