let f a b = if b > a then "+" ^ string_of_int(b-a) else if b = a then string_of_int(0) else "-" ^ string_of_int(b-a)
let () =
    let a, b = Scanf.scanf "%d %d\n" (fun a b -> a, b) in 
    Printf.printf "%s\n" (f a b)