import java.util.*;

public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        int k = sc.nextInt();
        int[] arr = new int[n];
        for (int i = 0; i < n; i++) {
            arr[i] = sc.nextInt();
        }
        Arrays.sort(arr);
        if (arr[n - 1] < 0) {
            System.out.println(arr[n - 1]);
            return;
        }
        long ans = 0;
        for (int i = 0; i < k && arr[n - 1 - i] > 0; i++) {
            ans += arr[n - 1 - i];
        }
        System.out.println(ans);
    }
}