num = int(input())
counter_i = 0
counter_j = 0
counter_k = 0
for i in "abcdefghijklmnopqrstuvwxyz":
    counter_i += 1
    if counter_i > num:
        break
    for j in "abcdefghijklmnopqrstuvwxyz":
        counter_j += 1
        if counter_j > num:
            counter_j = 0
            break
        for k in "abcdefghijklmnopqrstuvwxyz":
            counter_k += 1

            if counter_k > num:
                counter_k = 0
                break
            print(f"{i}{j}{k}")