#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 sum = 0;
  for (int i = 0; i < m; i++) {
    if (a[i] > 0) continue;
    sum += a[i];
  }
  cout << -sum << endl;
  return 0;
}
