using System;

public class Program

{

    public static void Main()

    {

        var res = GetResult("codeforces");

        Console.WriteLine(res);

    }

    public static string GetResult(string inputString)

        {

            var input = inputString.ToCharArray();

            bool anythingExceptA = false;

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

            {

                if (input[i] == 'a' && !anythingExceptA)

                {

                    continue;

                }

                else if (input[i] == 'a' && anythingExceptA)

                {

                    return new string(input);

                }

                else

                {

                    anythingExceptA = true;

                    input[i] = (char)(input[i] - 1);

                }

            }

​

            if (!anythingExceptA)

            {

                input[input.Length - 1] = 'z';

            }

​

            return new string(input);

        }

}