-- rot13.lua - rot13 implementation in lua :)
-- (c) 2003 Alexandre Erwin Ittner - aittner@netuno.com.br
-- Distributed under the terms of GNU GPL - WITHOUT ANY WARRANTY!


-- Applies the rot13 to the string - returns the rot13'd string
-- non-ascii characters will pass untouched
--
-- normal: ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz
-- rot13 : NOPQRSTUVWXYZABCDEFGHIJKLMnopqrstuvwxyzabcdefghijklm

function rot13(s)
  local str = ""
  local i = 1
  while i <= string.len(s) do
    if string.byte(string.upper(s), i) >= string.byte("A", 1) 
    and string.byte(string.upper(s), i) <= string.byte("Z", 1) then
      if string.byte(string.upper(s), i) <= string.byte("M", 1) then
        str = str .. string.char(string.byte(s, i) + 13)
      else
        str = str .. string.char(string.byte(s, i) - 13)
      end
    else
      str = str .. string.sub(s, i, i)
    end
    i = i + 1
  end
  return str
end



local a = ""
for l in io.lines() do
  a = a .. "\n" .. rot13(l)
end
print(a)