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-csc 3.5.0) (judge verdict: Wrong Answer)

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace atcoder
{
    public class Program
    {
        public static void Main(string[] args)
        {
            var buf = Console.ReadLine().Split(' ');
            int N = int.Parse(buf[0]);
            int M = int.Parse(buf[1]);

            buf = Console.ReadLine().Split(' ');
            var list = new List<int>();
            foreach (var v in buf)
                list.Add(int.Parse(v));
            var sum = list.Aggregate((i, s) => s += i);

            list.Sort();
            list.Reverse();

            foreach (var v in list.Take(M))
            {
                if (v < sum / (4 * M))
                {
                    Console.WriteLine("No");
                    return;
                }
            }

            Console.WriteLine("Yes");
        }
    }
}