class Program
{
    static void Main(string[] args)
    {
        string input = Console.ReadLine()!;
        List<int> numList = new List<int>();

        foreach (char c in input)
        {
            string change = c.ToString();
            int num = int.Parse(change);

            numList.Add(num);
        }
        numList.Sort();

        Console.WriteLine(numList[numList.Count - 1] - numList[0]);
    }
}