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



val () =
    let
        val n = readInt ()

        val isUsed = Array.array (n + 1, false)

        fun findAnsAux k =
            if n < k then ignore ()
            else
                (
                  Array.update (isUsed, n div k, true);
                  findAnsAux (k + 1)
                )

        fun findAns () =
            (
              findAnsAux 1;
              Array.foldl (fn (b, acc) => if b = true then acc + 1
                                          else acc)
                           0
                           isUsed
            )
        val ans = findAns ()
    in
        print (Int.toString ans ^ "\n")
    end