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

public class Program
{
    static void Main()
    {
        int Width = int.Parse(Console.ReadLine());
        int Group = int.Parse(Console.ReadLine());
        
        var ValueList = GetInt(Width).ToList().OrderByDescending(a => a);
        int Result = ValueList.First() - ValueList.Last();
        Console.WriteLine(Result);
    }
    
    static IEnumerable<char> GetChar(){
        int Moji = 0;
        int Count = 1;
        char tmp = (char)0;
        while((Moji = Console.Read()) != -1){
            if(Moji <65 || Moji >90){
                break;
            }
            tmp = (char)(( Moji - 65 + 26 - Count)%26 + 65);
            yield return tmp;
            Count = (Count + 1)%26;
        }
    }
    
    static IEnumerable<int> GetInt(int Loop){
        for(var i = 0; i < Loop ; i++){
            yield return int.Parse(Console.ReadLine());
        }
    }
    
    static void WriteLine <T>(T dsads){
        
    }
}