using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Linq;
using System.Numerics;

class Program
{
    static void Main()
    {
        string S = Console.ReadLine();
        int[] Numbers = Array.ConvertAll(S.ToCharArray(), r => int.Parse(r.ToString()));
        Console.WriteLine(Numbers.Max() - Numbers.Min());
    }
}