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

try:
   lines = fileinput.input()


   out = []
   for line in lines:
	if line  not in out:
		out.append(line)
		s= '%s' % (line[0:len(line)])
		s=s.replace("\n", "")
		print '%s' % (s)

except IOError:
   print "I/O error"