#include <stdio.h>
#include <algorithm>
using namespace std;

int n, k, a[111];

int main()
{
	scanf ("%d %d", &n, &k);
	for (int i = 0; i < n; i++) scanf ("%d", &a[i]);
	sort(a, a + n);
	reverse(a, a + n);
	int r = 0;
	for (int i = 0; i < k; i++) r += max(a[i], 0);
	if (a[0] < 0) r += a[0];
	printf ("%d\n", r);
	return 0;
}