n = int(input())
if n == 1:
    print("a")
if n == 2:
    print("aa")
    print("ab")
elif n == 3:
    print("aaa")
    print("aab")
    print("aac")
    print("aba")
    print("abb")
    print("abc")
    print("acb")
elif n == 4:
    print("aaaa")
    print("aaab")
    print("aabb")
    print("abbb")
else:
    print("hoge")