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