import math
from math import sqrt
import sys
from collections import deque, defaultdict
from heapq import heappop, heappush
from copy import deepcopy

INF=10**18
MOD=10**9+7
MAX=10**5+7

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

def main():
  N,K=map(int, input().split())
  A = list(map(int, input().split()))
  A.sort()
  A=A[::-1]
  ans=0

  if A[0]<0:
    print(A[0])
    sys.exit()


  for i in range(K):
    if A[i]>0: ans+=A[i]

  print(ans)


if __name__ == '__main__':
    main()