num = int(input())
base = ["a","b","c","d","e","f","g","h","j","k"]

if num == 1:
  print("a")
elif num == 2:
  print("aa")
  print("ab")
elif num == 3:
  print("aaa")
  print("aab")
  print("aba")
  print("abb")
  print("abc")
