# 26**4 > 10**5なのでa????aをn-1回やって、最後はanとして終わらせる
# ????は26進法のイメージ

alphabets = 'abcdefghijklmnopqrstuvwxyz'

def Dec_to_N(num, base):
    if num >= base:
        yield from Dec_to_N(num // base, base)
    yield num % base

N = int(input())
words = []
for i in range(N-1):
    num26 = list(Dec_to_N(i, 26))
    word26 = 'a'
    for n in num26:
        word26 += alphabets[n]
    word26 += 'a'
    words.append(word26)
    #print(i, num26)
    
words.append('an')

for w in words:
    print(w)