let (sx,sy,tx,ty) = Scanf.scanf "%d %d %d %d" (fun a b c d -> (a,b,c,d) )

let rec firstx x y tx ty list =
  if (x < tx) then firstx (x+1) y tx ty ('R'::list) else
    if (x > tx) then firstx (x-1) y tx ty ('L'::list) else list

let rec firsty x y tx ty list =
  if (y < ty) then firsty x (y+1) tx ty ('U'::list) else
    if (y > ty) then firsty x (y-1) tx ty ('D'::list) else list

let rec secondx x y tx ty list =
  if (x < (tx+1)) then firstx (x+1) y tx ty ('R'::list) else
    if (x > (tx+1)) then firstx (x-1) y tx ty ('L'::list) else list

let rec secondy x y tx ty list =
  if (y < ty) then firsty x (y+1) tx ty ('U'::list) else
    if (y > ty) then firsty x (y-1) tx ty ('D'::list) else list
      
let rec listinv = function
  | [] -> []
  | a :: rest ->
     match a with
     | 'R' -> 'L' :: listinv rest
     | 'L' -> 'R' :: listinv rest
     | 'U' -> 'D' :: listinv rest
     | 'D' -> 'U' :: listinv rest
      
let list1 = firstx sx sy tx ty [] 
let list2 = firsty sx sy tx ty []
let list12 = list1 @ list2 
let list12' = listinv list12
let list3 = 'D' :: (firstx sx sy tx ty []) @ ['R'] 
let list4 = 'U' :: (firsty sx sy tx ty []) @ ['L'] 
let list34 = list3 @ list4
let list34' = listinv list34
let anslist = list12 @ list12' @ list34 @ list34'

let rec list_to_string : char list -> string = fun cl ->
   String.concat "" @@ List.map (String.make 1) cl

let ans = list_to_string anslist
  
let () = Printf.printf "%s\n" ans
