N=int(input())
import random
alpha="abcdefghijklmnopqrstuvwxyz"
list=list(alpha)
start="a"
i=1
while i<=N:
    word=random.sample(list,i)
    word.insert(0,start)
    start=word[-1]
    if start=="n":
        word.append("a")
        start="a"
    if i==N:
        word.append("n")
    print("".join(word))
    i+=1