import java.util.*;

public class help
{
	
	public static void main(String[] arg)
	{
		Scanner sc = new Scanner(System.in);
		int pocet = sc.nextInt();
		while (pocet != 0)
		{
			int[] pole = new int[pocet];			
			for (int i = 0; i < pocet; i++)
			{
				pole[i] = sc.nextInt();
			}
			Arrays.sort(pole);
			boolean b = true;
			System.out.print(pole[0] + "-A ");
			for (int i = pocet - 1; i > 0; i--)
			{
				if (b)
				{
					System.out.print(pole[i] + "-B ");
					b = false;
				}
				else
				{
					System.out.print(pole[i] + "-A ");
					b = true;
				}
			}			
			System.out.println();
			pocet = sc.nextInt();
		}
	}
}