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

public class Program
{

	public void Proc()
	{
        int[] inpt = Reader.ReadLine().Split(' ').Select(a => int.Parse(a)).ToArray();
        int mojiLen = inpt[0];
        int circleCount = inpt[1];

        string ans = "";
        if(mojiLen >= circleCount) {
            ans = ans.PadLeft(circleCount, 'A').PadRight(mojiLen, 'C');
        } else {
            int bCount = circleCount - mojiLen;
            ans = ans.PadLeft(bCount, 'B').PadLeft(mojiLen, 'A');
        }
        Console.WriteLine(ans);
    }

	public class Reader
	{
		private static StringReader sr;
		public static bool IsDebug = false;
		public static string ReadLine()
		{
			if (IsDebug)
			{
				if (sr == null)
				{
					sr = new StringReader(InputText.Trim());
				}
				return sr.ReadLine();
			}
			else
			{
				return Console.ReadLine();
			}
		}
		private static string InputText = @"



5 6



";
	}

	public static void Main(string[] args)
	{
#if DEBUG
		Reader.IsDebug = true;
#endif
		Program prg = new Program();
		prg.Proc();
	}
}