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

namespace yukicoderTest
{
    class Program
    {
        static void Main(string[] args)
        {
            string n = Console.ReadLine();
            string k = Console.ReadLine();
            int num = int.Parse(n);
            int group = int.Parse(k);
            int[] ary = new int[num];
            for (int i = 0; i < num; i++)
            {
                var line = Console.ReadLine();
                ary[i] = int.Parse(line);
            }

            for (int i = 0; i < ary.Length; i++)
            {

                for (int j = i + 1; j < ary.Length; j++)
                {
                    if (ary[i] < ary[j])
                    {
                        int temp = ary[i];
                        ary[i] = ary[j];
                        ary[j] = temp;
                    }


                }
            }

            Console.WriteLine(ary[0] - ary[ary.Length - 1]);

        }
    }
}