fun readLargeInt () =
    valOf (TextIO.scanStream (LargeInt.scan StringCvt.DEC) TextIO.stdIn)


val () =
    let
        val a = LargeWord.fromLargeInt (readLargeInt ())
        val c = LargeWord.fromLargeInt (readLargeInt ())

        val b = LargeWord.xorb (a, c)
    in
        print (LargeInt.toString (LargeWord.toLargeIntX b) ^ "\n")
    end