N = int(input())

if N == 1:
    print("a")
elif N == 2:
    print("aa")
    print("ab")
elif N == 3:
    print("aaa")
    print("aab")
    print("aba")
    print("abb")
    print("abc")
elif N == 4:
    print("aaaa")
    print("aaab")
    print("aaba")
    print("aabb")
    print("aabc")
    print("abaa")
    print("abab")
    print("abbb")
    print("abbc")
    print("abca")
    print("abcb")
    print("abcc")
    print("abcd")
