# coding: utf-8
# Your code here!
import sys
read = sys.stdin.read
readline = sys.stdin.readline 
readlines = sys.stdin.readlines

#n = int(input())
#ab = [[int(i) for i in readline().split()] for _ in range(n)]
n,k,*a = [int(i) for i in read().split()]

a.sort()
ans = a.pop()


for i in range(k-1):
    v = a.pop()
    if v > 0: ans += v
    else: break

print(ans)