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


fun quicksort [] = []
  | quicksort (h::tl) =
    let 
        val (s, b) =
            List.foldl
                (fn (x, (small, big)) =>
                    if x <= h then (x::small, big)
                    else (small, x::big))
                ([], [])
                tl
    in
        (quicksort s) @ [h] @ (quicksort b)
    end


fun findAns [] = 0
  | findAns [_] = 0
  | findAns (h1::h2::tl) = if h1 = h2 then 1 + findAns tl
                           else findAns (h2::tl)


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

        val sorted = quicksort a_s

        val ans = findAns sorted
    in
        print (Int.toString ans ^ "\n")
    end