#include <bits/stdc++.h>
using namespace std;
using ll = long long;
constexpr long long MOD = 1000000007;
int main(){
ll n,k;
cin >> n >> k;
ll a[n];
for (ll i = 0; i < n; i++) cin >> a[i];
sort(a, a + n, greater<ll>());
ll ans = 0;
for (ll i = 0; i < k; i++) {
    if (a[i] < 0) break;
    ans += a[i];
}
cout << ans << endl;
}