#include <iostream>
#include <vector>
#include <algorithm>

using namespace std; using ll=long long; const ll LNF=1e18; const int INF = 1e9+1; const ll M = 1e9+7;
typedef pair<int,int> P;

int main() {
  int n,k; cin>>n>>k;
  int a[n]; for(int i=0;i<n;i++) cin>>a[i];
  sort(a,a+n,greater<int>());
  int an=0;
  for(int i=0;i<k;i++) {
    if (i>0 && a[i]<0) break;
    an += a[i];
  }
  cout<<an<<endl;
}