from typing import List


def diff_one(l: List[str]) -> bool:
    prev = l[0]

    for i in range(1, len(l)):
        if abs(ord(l[i]) - ord(prev)) >= 2:
            return False
        prev = l[i]

    return True


def comb(current: List[str], rest: List[str], target: int):
    if len(current) == target:
        yield current
    elif len(current) < target and len(rest) > 0:
        for i in range(len(current) + 1):
            yield from comb(current + [rest[i]], rest, target)


if __name__ == '__main__':
    n = int(input())
    alphabet = [str(chr(i)) for i in range(97, 97 + 26)]

    for perm in comb([], alphabet[:n], n):
        if diff_one(perm):
            print("".join(perm))
