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")
elif num == 4:
  print("aaaa")
  print("aaab")
  print("aaba")
  print("aabb")
  print("aabc")
  print("abaa")
  print("abab")
  print("abac")
  print("abba")
  print("abbb")
  print("abbc")
  print("abca")
  print("abcb")
  print("abcc")
  print("abcd")