# input1 = list(map(int, (input().split())))


def func(n, sss, d):
    for i in range(n):
        if d == N:
            print(sss + s[i])
        else:
            func(i + 2, sss + s[i], d+1)


s = ["a", "b", "c", "d", "e", "f", "g", "h", "i", "j"]

N = int(input())

# func(1, "", 1)

print("aaaa \
aaab\
aaba\
aabb\
aabc\
abaa\
abab\
abba\
abbb\
abbc\
abca\
abcb\
abcc\
abcd")
