using System.Numerics;

public class Program
{
    public static void Main()
    {
        //int num = int.Parse(Console.ReadLine() ?? string.Empty);
        string[] str = (Console.ReadLine() ?? string.Empty).Trim().Split(' ');
        string[] str2 = (Console.ReadLine() ?? string.Empty).Trim().Split(' ');
        //string color = Console.ReadLine() ?? string.Empty;

        int need = int.Parse(str[1]);
        int[] ints = new int[str2.Length];
        for (int i = 0; i < str2.Length; i++)
        {
            if (int.Parse(str2[i]) < 0)
            {
                continue;
            }
            ints[i] = int.Parse(str2[i]);
        }
        Array.Sort(ints);

        int count = 0;
        for (int i = need; i > 0; i--)
        {
            if (i > ints.Length - 1 || ints[i] < 0)
            {
                break;
            }
            count += ints[i];
        }
        Console.WriteLine(count);
    }
}