# -*- coding: utf-8 -*-
from itertools import combinations_with_replacement
from string import ascii_lowercase
def inpl(): return map(int, input().split())

N = int(input())

i = 0
for x in combinations_with_replacement(ascii_lowercase, 18):
    i += 1
    if i == N:
        print("a{}n".format("".join(x)))
        break
    print("a{}a".format("".join(x)))