#include <bits/stdc++.h>
using namespace std;
int main() {
  int n, m;
  cin >> n >> m;
  int a[n];
  for (int i = 0; i < n; ++i) cin >> a[i];
  sort(a, a + n);
  int counter = 0;
  for (int i = 0; i < n; ++i) {
    if (m > 0 && a[i] <= 0) {
      counter -= a[i];
      m--;
    }
  }
  cout << counter;
  return 0;
}
