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


val () =
    let
        val n = readInt ()
        val a_s = List.tabulate (n, fn _ => readInt ())
        val b_s = List.tabulate (n, fn _ => readInt ())

        val ans = ListPair.foldl
                      (fn (a, b, acc) =>
                          if a <= b then acc + 1
                          else acc)
                      0
                      (a_s, b_s)
    in
        print (Int.toString ans ^ "\n")
    end