fun readStr () =
    valOf (TextIO.inputLine TextIO.stdIn)

fun insertionSort l =
    let
        fun insert x [] = [x]
          | insert x (y::ys) = if x <= y then x::y::ys
                               else y::(insert x ys)
    in
        foldl (fn (x, acc) => insert x acc) [] l
    end

val () =
    let
        val a = readStr ()
        val b = readStr ()
        val sortedA = (insertionSort o explode) a
        val sortedB = (insertionSort o explode) b

        val ans = if sortedA = sortedB then "YES\n"
                  else "NO\n"
    in
        print ans
    end