let shift s i =
  String.map (fun c ->
      let cc = (Char.code c) in
      if cc >= 65 && cc <= 90 then
        (cc - 39 + i) mod 26 |> (+) 65 |> Char.chr
      else if cc >= 97 && cc <= 122 then
        (cc - 71 +i)  mod 26 |> (+) 97 |> Char.chr
      else c) s
;;

let () =
  let line = read_line () in
  print_endline (shift line (-3))
;;