#yuki701
import sys

s='bcdefghijklmopqrstuvwxyz'
n=int(raw_input())
if n==1:
 print 'an'
 sys.exit()
t='b'
i=0
flg=False
for j in xrange(24):
 for k in xrange(24):
  for l in xrange(24):
   for m in xrange(24):
    t=s[j]+s[k]+s[l]+s[m]
    print 'a'+t+'a'
    i+=1
    if i>(n-2):
     print 'an'
     sys.exit()