N = int(input())


# 最後は an
# 最後以外は a ***** a
# ***** には 0 ~ 9 を入れる
d = {}
d['0'] = 'a'
d['1'] = 'b'
d['2'] = 'c'
d['3'] = 'd'
d['4'] = 'e'
d['5'] = 'f'
d['6'] = 'g'
d['7'] = 'h'
d['8'] = 'i'
d['9'] = 'j'

for i in range(N - 1):
    res = ['a']
    for s in str(i):
        res.append(d[s])
    res.append('a')
    print(''.join(res))

print('an')