fun readInt () =
    valOf (TextIO.scanStream (Int.scan StringCvt.DEC) TextIO.stdIn)


val () =
    let
        val aw = readInt ()
        val ab = readInt ()
        val bw = readInt ()
        val bb = readInt ()
        val c = readInt ()
        val d = readInt ()

        val bStone_a_to_b = Int.min (c, ab)
        val wStone_a_to_b = c - bStone_a_to_b

        val wStone_after_a_to_b_in_a = aw - wStone_a_to_b
(*
        val bStone_after_a_to_b_in_a = ab - bStone_a_to_b
*)
        val wStone_after_a_to_b_in_b = bw + wStone_a_to_b
(*
        val bStone_after_a_to_b_in_b = bb + bStone_a_to_b
*)

        val ans = wStone_after_a_to_b_in_a + Int.min (d, wStone_after_a_to_b_in_b)
    in    
        print (Int.toString ans ^ "\n")
    end