fun readStr () =
    let
        fun scan reader stream = SOME (StringCvt.splitl (not o Char.isSpace) reader (StringCvt.skipWS reader stream))
    in
        valOf (TextIO.scanStream scan TextIO.stdIn)
    end


fun find_ans s =
    let
        fun find_ans_aux [] current max = Int.max (current, max)
          | find_ans_aux (h::t) current max =
            if h = #"o" then  find_ans_aux t (current + 1) max
            else find_ans_aux t 0 (Int.max (current, max))
    in
        find_ans_aux (String.explode s) 0 0
    end


val () =
    let
        val s1 = readStr ()
        val s2 = readStr ()

        val ans = find_ans (s1 ^ s2)
    in
        print (Int.toString ans ^ "\n")
    end