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.Collections;
using System.Collections.Generic;
using System.Linq;

namespace competitive_programming
{
    class Program
    {
        static void Main(string[] args)
        {
            var main = new Program();
            main.solve();
        }

        void solve()
        {
            int[] nm = Console.ReadLine().Split(' ').Select(val => int.Parse(val)).ToArray();
            int n = nm[0];
            int m = nm[1];

            int[] As = Console.ReadLine().Split(' ').Select(val => int.Parse(val)).ToArray();
            int sum = As.Sum();
            int count = 0;
            for(int i = 0;i < As.Length;i++)
            {
                if (As[i] >=(double)( 1 / (4*m))) count++;
            }
            Console.WriteLine(count >= m ? "Yes" : "No");
        }
    }

    struct Vector2
    {
        public Vector2(long x, long y)
        {
            this.x = x;
            this.y = y;
        }
        public long x;
        public long y;
    }

    struct Vector3
    {
        public int x;
        public int y;
        public int z;
    }
}