using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace exam
{
    class Program
    {
        static void Main(string[] args)
        {
            char last = char.Parse(Console.ReadLine());
            int seats = int.Parse(Console.ReadLine());
            char oddseats =char.Parse(Console.ReadLine());
            char c = Convert.ToChar(50 + oddseats);
            int sectorCount = 0;
            int seatsCount = 0;

            for(char a='A';a<=last;a++)
            {
                sectorCount++;
                if(sectorCount>1)
                {
                    seats++;
                }
                for (int i = 1; i <= seats; i++)
                {
                    if (i!= 1 &&i % 2 == 0)
                    {
                        for (char b = 'a'; b <c; b++)
                        {
                            Console.WriteLine($"{a}{i}{b}");
                            seatsCount++;
                        }
                    }
                    else
                    {
                        for (char b = 'a'; b < c; b++)
                        {
                            if (b == 'c' || b == 'd')
                            {
                                break;
                            }
                            Console.WriteLine($"{a}{i}{b}");
                            seatsCount++;
                        }
                    }
                }
            }
            Console.WriteLine(seatsCount);
        }
    }
}