package net.ipipip0129.yukicoder.no701;

import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner scan = new Scanner(System.in);
        int num_cnt = scan.nextInt();


        CreateMoji createMoji = new CreateMoji();

        for (int i = 0; i < num_cnt - 1; i++) {
            String moji = createMoji.createNextMoji('a', 'a');
            System.out.println(moji);
        }
        System.out.println(createMoji.createNextMoji('a', 'n'));
    }
}

class CreateMoji {
    private int[] integer_array;

    CreateMoji() {
        this.integer_array = new int[18];
    }

    public String createNextMoji(char beginChar, char endChar) {
        StringBuilder sb = new StringBuilder();

        sb.append(beginChar);

        for (int i = 0; i < 18; i++) {
            sb.append(Character.toChars(97 + integer_array[i]));
        }

        sb.append(endChar);

        integer_array[0] += 1;

        moveUp();

        return sb.toString();
    }

    private void moveUp() {
        for (int i = 0; i < 18; i++) {
            if (integer_array[i] == 26) {
                integer_array[i + 1] += 1;
                integer_array[i] = 0;
            }
        }
    }
}