from itertools import product

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

    cnt = 0
    for i1, i2, i3, i4 in product(range(97, 123), repeat=4):
        s1, s2, s3, s4 = chr(i1), chr(i2), chr(i3), chr(i4)
        s = 'a' + s1 + s2 + s3 + s4 + 'a'
        if cnt < N - 1:
            print(s)
            cnt += 1
        else:
            print(s + 'n')
            break

main()