#include <iostream>
#include <algorithm>
#include <numeric>
#include <vector>

void solve() {
    int n, k;
    std::cin >> n >> k;

    std::vector<int> xs(n);
    for (auto& x : xs) {
        std::cin >> x;
        x = std::max(x, 0);
    }
    std::sort(xs.rbegin(), xs.rend());

    std::cout << std::accumulate(xs.begin(), xs.begin() + k, 0)
              << std::endl;
}

int main() {
    std::cin.tie(nullptr);
    std::ios::sync_with_stdio(false);

    solve();

    return 0;
}