n = int(input())
for i in range(n):
    tmp = i
    result = []
    for j in range(3,-1,-1):
        result.append(chr(ord('a') + (tmp//pow(26,j))))
        tmp %= pow(26,j)
    if i < n-1:
        print('a' + ''.join(result) + 'a')
    else:
        print('a' + ''.join(result) + 'n')