#include <bits/stdc++.h>

int main(){
  int n, k; std::cin >> n >> k;
  std::vector<int> a(n);
  for(int i = 0; i < n; ++i){
    std::cin >> a[i];
    if(a[i] < 0) a[i] = 0;
  }
  std::sort(a.rbegin(), a.rend());

  int ans = std::accumulate(a.begin(), a.begin() + k, 0);
  std::cout << ans << "\n";

  return 0;
}