from itertools import cycle

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

    cnt = 0
    for i in cycle(range(97, 122)):
        s = chr(i) + chr(i+1)
        print(s)
        if cnt < N - 2:
            cnt += 1
        else:
            print(chr(i+1) + 'n')
            break
main()