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 PHP7 (7.0.15) (judge verdict: Accepted)

<?php

class scan {
    private $arr = [];
    private $count = 0;
    private $pointer = 0;
    public function next() {
        if($this->pointer >= $this->count) {
            $str = trim(fgets(STDIN));
            $this->arr = explode(' ', $str);
            $this->count = count($this->arr);
            $this->pointer = 0;
        }
        $result = $this->arr[$this->pointer];
        $this->pointer++;
        return $result;
    }
    public function hasNext() {
        return $this->pointer < $this->count;
    }
    public function nextInt() {
        return (int)$this->next();
    }
    public function nextDouble() {
        return (double)$this->next();
    }
}

$sc = new scan();
$n = $sc->nextInt();
$m = $sc->nextInt();
$sum = 0;
for ($i=0;$i<$n;$i++) {
    $a[] = $sc->nextInt();
    $sum += $a[$i];
}

rsort($a);
if ($a[$m - 1] < (1/(4*$m)*$sum)) {
    echo "No";
} else {
    echo "Yes";
}