#!/usr/bin/env python
import itertools
import sys

def generate_kmers(kmer):
  """ generate all possible kmers permutations seperated by newlines 

 >>> kmers =  generate_kmers(1)
 >>> generate_kmers(2)

 param kmer: the desired Mer size
 type  kmer: int
 return: Returns a string of kmers seperated by newlines
 rtype: string
 """

  return '\n'.join(''.join(x) for x in itertools.product('acgt', repeat=kmer))
    
if(len(sys.argv) < 2):
  print "usage: generate_kmers KMER_SIZE"
  exit(1)

print generate_kmers(int(sys.argv[1]))