# coding: utf-8
import string
import itertools

n = int(input())
num = [i for i in range(11)]
s = string.ascii_lowercase
lis = list(itertools.combinations_with_replacement(num[0:n-1], n-1))

if n != 1:
    for li in lis:
        for i in range(n-2):
            if li[i+1] - li[i] >= 2 or li[0] >= 2:
                break
        else:
            print('a', end='')
            for i in range(n-1):
                print(s[li[i]], end='')
            print('')

print(s[:n])