# coding: utf-8
N,K=map(int,input().split())
A=list(map(int,input().split()))

A.sort()
m=A[-1]
cnt=0
for i in range(N):
    if A[i]<0:
        cnt+=1
        A[i]=0

if cnt==N:
    print(m)
else:
    print(sum(A[N-K:]))