let () =
  read_line ()
  |> String.map (fun c ->
    if c >= 'a' && c <= 'z' then Char.code c - Char.code 'a' + Char.code 'A' |> Char.chr
    else Char.code c - Char.code 'A' + Char.code 'a' |> Char.chr)
  |> print_endline