using System;

public class Program

{

    public void Chocolate(int[] arr,int key)

    {

        Array.Sort(arr);

        int mindiff=int.MaxValue;

        for(int i=0;i<arr.Length-key;i++)

        {

            //Console.WriteLine("{0},{1}",arr[i],arr[i+key]);

            if(mindiff>arr[i+key]-arr[i])

            {

                mindiff=arr[i+key]-arr[i];

            }

        }

        Console.WriteLine(mindiff);

    }

    public static void Main()

    {

        int[] arr=new int[]{3, 4, 1, 9, 56};

        int people=5;

        Program p =new Program();

        p.Chocolate(arr,people-1);

    }

}