from itertools import product

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

    cnt = 0
    for i2, i3, i1 in product(range(97, 123), repeat=3):
        s1 = chr(i1)
        s2 = chr(i2)
        s3 = chr(i3)
        s4 = chr(i1 + 1) if i1 < 122 else 'a'
        s = s1 + s2 + s3 + s4
        if cnt < N - 1:
            print(s)
            cnt += 1
        else:
            print(s + 'n')
            break

main()