let rec p () = Scanf.sscanf (read_line ()) "%d %s %d" (fun a op b ->
  match op with
  | "+" -> print_endline (string_of_int (a + b)); p ()
  | "-" -> print_endline (string_of_int (a - b)); p ()
  | "*" -> print_endline (string_of_int (a * b)); p ()
  | "/" -> print_endline (string_of_int (a / b)); p ()
  | _ -> ()
)
let _ = p()
