Problem:
Score : 200 points

Problem Statement

We have held a popularity poll for N items on sale. Item i received A_i votes.

From these N items, we will select M as popular items. However, we cannot select an item with less than \dfrac{1}{4M} of the total number of votes.

If M popular items can be selected, print Yes; otherwise, print No.

Constraints

1 \leq M \leq N \leq 100

1 \leq A_i \leq 1000

A_i are distinct.

All values in input are integers.

Input

Input is given from Standard Input in the following format:

N M
A_1 ... A_N

Output

If M popular items can be selected, print Yes; otherwise, print No.

Sample Input 1

4 1
5 4 2 1

Sample Output 1

Yes

There were 12 votes in total. The most popular item received 5 votes, and we can select it.

Sample Input 2

3 2
380 19 1

Sample Output 2

No

There were 400 votes in total. The second and third most popular items received less than \dfrac{1}{4\times 2} of the total number of votes, so we cannot select them. Thus, we cannot select two popular items.

Sample Input 3

12 3
4 56 78 901 2 345 67 890 123 45 6 789

Sample Output 3

Yes

Solution in Common Lisp (SBCL 1.1.14) (judge verdict: Accepted)

;; B - Popular Vote

(defun can-choose (m a)
  "総得票数の1/(4*m)以上票を得た商品がm個以上あるか"
  (let* ((total (reduce #'+ a))
         (thres (ceiling total (* 4 m)))
         (npop  (count-if #'(lambda (x) (>= x thres)) a)))
    (>= npop m)))

(let* ((n (read))
       (m (read))
       (a (loop repeat n collect (read))))
  (princ (if (can-choose m a) "Yes" "No")))