import sys
import pypyjit
import itertools
import heapq
import math
from collections import deque, defaultdict
import bisect
import random

input = sys.stdin.readline
sys.setrecursionlimit(10 ** 6)
pypyjit.set_param('max_unroll_recursion=-1')


def index_lt(a, x):
    'return largest index s.t. A[i] < x or -1 if it does not exist'
    return bisect.bisect_left(a, x) - 1


def index_le(a, x):
    'return largest index s.t. A[i] <= x or -1 if it does not exist'
    return bisect.bisect_right(a, x) - 1


def index_gt(a, x):
    'return smallest index s.t. A[i] > x or len(a) if it does not exist'
    return bisect.bisect_right(a, x)


def index_ge(a, x):
    'return smallest index s.t. A[i] >= x or len(a) if it does not exist'
    return bisect.bisect_left(a, x)


def generate(k):
    return random.sample(range(26), k)


N = int(input())
S = ['a']
for i in range(N):
    S = [S[-1]]
    for j in generate(18):
        S.append(chr(ord('a') + j))
    if i == N - 1:
        S[-1] = 'n'
    else:
        S[-1] = 'a'
    print(''.join(S))