#include <bits/stdc++.h>
using namespace std;
typedef long long int ll;
ll mod = 1000000007;

ll r(ll x, ll y) {
  if (y == 0) return 1;
  else if (y % 2 == 0) return r(x, y/2) * r(x, y/2) % mod;
  else return x * r(x, (y-1)/2) % mod * r(x, (y-1)/2) % mod;
}

int main() {
  int n, k;
  cin >> n >> k;
  priority_queue<int> pq;
  for (int i = 0; i < n; i++) {
    int a;
    cin >> a;
    pq.push(a);
  }
  int count = 0;
  for (int i = 0;i < k; i++) {
    if (pq.top() < 0) {
      break;
    }
    count += pq.top();
    pq.pop();
  }
  cout << count <<endl;
}