N,K = map(int,input().split())
List = list(map(int,input().split()))

List = sorted(List)
ans = List[-1]
if K == 1:
    print(ans)
    exit()
for i in range(K-1):
    if List[-(i+1)] <= 0:
        break
    else:
        ans += List[-(i+1)]
print(ans)