#include <bits/stdc++.h>
#define rep(i, n) for (int i = 0; i < n; ++i)
using ll = long long;
using namespace std;
const int INF = 1e9;

int main() {
    int N, K;
    cin >> N >> K;
    vector<int> A(N);
    rep(i, N) cin >> A[i];
    sort(A.rbegin(), A.rend());

    ll ans = 0;
    rep(i, K) {
        if (A[i] >= 0)
            ans += A[i];
        else {
            if (i == 0)
                ans += A[i];
            break;
        }
    }

    cout << ans << endl;

    return 0;
}