#!/usr/bin/env python
# coding: utf-8

# In[56]:


N = int(input())


# In[59]:


num2alpha = lambda c: chr(c%26+97)


# In[61]:


ans = []
for i in range(2**(N-1),2**N):
    mylist = list(format(i,"b"))
    word = ""
    cnt = -1
    for x in mylist:
        if x == "1":
            cnt += 1
        word += num2alpha(cnt)
    ans += [word]
for w in ans:
    print(w)


# In[ ]:




