from itertools import product
a = "abcdefghijklmnopqrstuvwxyz"
print(*[ "a" + a[i] + a[j] + a[k] + a[l] + "a" for _, (i, j, k, l) in zip([0] * (int(input())-1), product(range(0,26), repeat=4))], "an", sep="\n")