<tswett> le/rn fundamental theorem of Taneb/The Fundamental Theorem of Taneb states that for all strings S, if S describes a thing, then it is provable that Taneb invented the thing described by S; and, furthermore, that it is provable that there exists a string T that describes a thing that Taneb did not invent.

#!/usr/bin/python
s=set()
try:
 while True:
  l=raw_input()
  if l not in s:
   s.add(l)
   print(l)
except EOFError:
 pass