#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 < min(n, m) && a[i] < 0; i++) sum += a[i] * -1;
  cout << sum;
}
