//BooksSet.java

import java.util.Scanner;
import java.util.HashSet;

public class BooksSet
{
    public static void main(String[] args)
    {
        Scanner scnr = new Scanner(System.in);
        HashSet<String> books = new HashSet<String>();
        String userInput;

        userInput = scnr.nextLine();
        while (userInput.compareTo("done") != 0)
        {
            if (books.add(userInput))
            {
                System.out.println("a");
            }
            else
            {
                System.out.println("n");
            }
            userInput = scnr.nextLine();
        }

        System.out.println("Size: " + books.size());
    }
}