#coding: UTF-8
import sys
import os
import random
siritori=[]
last=''
moji = 'abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ'
a=int(input())
for i in range(a):
    next=(last+''.join(random.choices(moji, k=random.randrange(19))))
    while next in siritori:
        next=(last+''.join(random.choices(moji, k=random.randrange(19))))
    siritori.append(next)
    print(siritori[i])
    last=siritori[i][-1:]