#include <bits/stdc++.h>
using namespace std;

int main()
{
	int N, K;
	cin >> N >> K;
	vector<int> A( N );
	for( int i = 0; i < N; i++ ) {
		cin >> A[i];
	}

	sort( A.rbegin(), A.rend() );
	int ans = 0;
	for( int i = 0; i < K; i++ ) {
		if( A[i] < 0 ) break;
		ans += A[i];
	}

	cout << ans << endl;
}