defmodule Main do 
  def main do
    IO.gets("") |> String.trim |> String.codepoints |> Enum.map(&Main.updowncase(&1)) |> IO.puts
  end
  
  def updowncase(char) do
    if String.match?(char, ~r/[a-z]/) do
      String.upcase(char)
    else
      String.downcase(char)
    end
  end
end