#include <bits/stdc++.h>
#define rep(i,n) for(int i = 0; i < n; i++)
#define REP(i,s,n) for(int i = s; i < n; i++)
typedef long long ll;
using namespace std;
using Graph = vector<vector<int>>;
ll gcd(ll a, ll b) { return b ? gcd(b, a%b) : a; }
ll lcm(ll a, ll b) { return (a * b) / gcd(a,b); }
ll ceil(const ll a, const ll b) { return (a + b - 1) / b; }
int main(){
  int n,k;
  cin >> n >> k;
  vector<int>v(n);
  rep(i,n)cin >> v[i];
  int ans = 0;
  sort(v.rbegin(),v.rend());
  rep(i,k)if(v[i] >= 0)ans += v[i];
  cout << ans << endl;
  return 0;
}