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 C# (Mono 4.6.2.0) (judge verdict: Wrong Answer)

using System;
using System.Linq;
 
public class Hello{
    public static void Main(){
        var input = Console.ReadLine().Split(' ').Select(x=>Int32.Parse(x)).ToList();
        var n = input[0];
        var m = input[1];
        var a = Console.ReadLine().Split(' ').Select(x=>Int32.Parse(x)).OrderByDescending(x=>x).ToList();
        
        var sum = a.Sum();
        var ret = true;
        for(var i = 1; i <= m; ++i){
            var border = (int)sum / (4 * i);
            if (a[i - 1] < border) ret = false; 
        }

        Console.WriteLine(ret? "Yes": "No");
    }
}