from itertools import product

def main():
    N = int(input())

    cnt = 0
    for i1, i2, i3, i4 in product(range(97, 123), repeat=4):
        s = 'a' + chr(i1) + chr(i2) + chr(i3) + chr(i4) + 'a'
        if cnt < N - 1:
            print(s)
            cnt += 1
        else:
            print('an')
            break

main()