using System;

public class Program
{
	public static void Main()
	{
		char lastSector = Console.ReadLine().ToCharArray()[0];
		byte rowsInFirstSector = byte.Parse(Console.ReadLine());
		byte seatsOnUnevenRows = byte.Parse(Console.ReadLine());

		int numberOfRowsInCurrentSector = rowsInFirstSector;
		int numberOfSeats = 0;

		for (char currentSector = 'A'; currentSector<=lastSector; currentSector++)
		{
			for (int currentRow = 1; currentRow<=numberOfRowsInCurrentSector;currentRow++)
			{
				int lastSeat;
				if (currentRow%2==1) lastSeat = (int)'a'+seatsOnUnevenRows-1;
				else lastSeat = (int)'a'+seatsOnUnevenRows+1;
				for (char currentSeat = 'a'; (int)currentSeat<=lastSeat;)
				{
					Console.WriteLine("{0}{1}{2}",currentSector,currentRow,currentSeat);
					currentSeat = (char)((int)currentSeat+1);
					numberOfSeats++;
				}
			}
			numberOfRowsInCurrentSector++;
		}
		Console.WriteLine(numberOfSeats);
	}
}