#include<bits/stdc++.h>
using namespace std;
int a[105];
bool cmp(int x, int y){
	return x > y;
}
int main(){
	int n, m;
	cin >> n >> m;
	for(int i = 1; i <= n; i++){
		int x;
		cin >> x;
		a[i] = 0 - x;
	}
	sort(a+1, a+1+n, cmp);
	int money = 0;
	for(int i = 1; i <= m; i++)
		if(a[i] >= 0) money += a[i];
		else break;
	cout << money;		
	return 0;
}