#!/usr/bin/env python2.7
# -*- coding: utf-8 -*-


def convert(src, dst):
  import csv
  from itertools import chain, izip_longest
  # NOTE: see also document itertools recipe "grouper" function.
  # NOTE: python3 built-in "zip" returns an iterator object
  
  parse = lambda x: x.strip().split(" ")
  output = csv.writer(dst).writerow
  
  for e in izip_longest(*[iter(src)]*2):
  	output(list(chain(*map(parse,e))))


if __name__ == "__main__":
	
  if 0:
    with open("data.dat") as src, open("out.csv","w") as dst:
      convert(src, dst)

  if 1: # for ideone.com
  	import sys
  	convert(sys.stdin, sys.stdout)