#include <bits/stdc++.h>
using namespace std;
template<typename T1,typename T2> inline void chmin(T1 &a,T2 b){if(a>b) a=b;}
template<typename T1,typename T2> inline void chmax(T1 &a,T2 b){if(a<b) a=b;}
using Int = long long;
const char newl = '\n';


template<typename T> void drop(const T &x){cout<<x<<endl;exit(0);}

//INSERT ABOVE HERE
signed main(){
  cin.tie(0);
  ios::sync_with_stdio(0);

  Int n,k;
  cin>>n>>k;
  vector<Int> as(n);
  for(Int i=0;i<n;i++) cin>>as[i];

  sort(as.rbegin(),as.rend());
  if(as[0]<=0) drop(as[0]);

  Int sum=0;
  for(Int i=0;i<k;i++){
    if(as[i]<0) break;
    sum+=as[i];
  }

  cout<<sum<<newl;
  return 0;
}