from random import choices
from string import ascii_lowercase


class ShiritoriWordManage:
    def __init__(self, length: int, word_length: int = None) -> None:
        self.word_used = set()
        self.current_letter = "a"
        self.current_iter = 0
        self.end_iter = length
        if word_length is None:
            self.word_length = 6
        else:
            self.word_length = word_length

    def create_word(self, start_letter=None, end_letter=None) -> str:
        next_word = ""
        if start_letter is None:
            start_letter = self.current_letter
        while not next_word or next_word in self.word_used:
            if end_letter is None:
                next_word = start_letter + \
                    "".join(choices(ascii_lowercase, k=self.word_length - 1))
            else:
                next_word = start_letter + \
                    "".join(choices(ascii_lowercase,
                            k=self.word_length - 2)) + end_letter

        return next_word

    def exec_shiritori(self):
        for self.current_iter in range(self.end_iter):
            if self.current_iter == self.end_iter - 1:
                print(self.create_word(self.current_letter, "n"))
                return

            next_word = "n"
            while next_word[-1] == "n":
                next_word = self.create_word()

            self.current_letter = next_word[-1]
            self.word_used.add(next_word)
            print(next_word)


def main():
    n = int(input())
    shiritori = ShiritoriWordManage(n)
    shiritori.exec_shiritori()


if __name__ == "__main__":
    main()