#include <bits/stdc++.h>
using namespace std;
using ll = long long;
#define rep(i, n) for (int i = 0; i < (int)(n); i++)

int main() {
  int n,k;
  cin>>n>>k;
  vector<int> a(n);
  rep(i,n){
    int A;
    cin>>A;
    a[i]=A;
  }
  sort(a.begin(),a.end());
  reverse(a.begin(),a.end());
  int max_o=0;
  rep(i,k){
    if(a[i]<0 && i!=0){
      break;
    }
    max_o+=a[i];
  }
  cout<<max_o<<endl;
}