class Program
    {
        static void Main(string[] args)
        {
            char[] list = { 'C', 'A', 'B' };
            string[] str = Console.ReadLine().Split(' ');
            char[] charList = Enumerable.Repeat(list[1],int.Parse(str[0])).ToArray();
            int remaining = int.Parse(str[1]) - int.Parse(str[0]);
            int i = 0;
            while(remaining != 0)
            {
                if(remaining > 0)
                {
                    charList[i] = list[2];
                    remaining--;
                }
                else
                {
                    charList[i] = list[0];
                    remaining++;
                }
                i++;
            }
            Array.Sort(charList);
            string ans = string.Join("",charList);
            Console.WriteLine(ans);
        }
    }