#yuki1046
n,k=map(int,input().split())
a=list(map(int,input().split()))
b=sorted(a,reverse=True)
if b[0]<=0:
 print(b[0])
else:
 res=0
 for i in range(k):
  if b[i]>0:
   res+=b[i]
 print(res)