# coding: utf-8
N,K = gets.split(' ').map{|s|s.to_i}
A = gets.split(' ').map{|s|s.to_i}

topK = A.sort!{|l, r| r <=> l}
         .take(K)

if topK[0] < 0 then
  p topK[0]
else
  p topK.select{|i| i > 0}
      .sum()
end