let n = stdin.ReadLine () |> int
let a = stdin.ReadLine().Split " " |> Array.map int |> Array.sort


[|
    for i in 0..a.Length-1 ->
        if a.Length = 1 then
            true
        elif i = 0 then
            a.[i] <> a.[i+1]
        elif i = a.Length-1 then
            a.[i] <> a.[i-1]
        else
            a.[i] <> a.[i-1] && a.[i] <> a.[i+1]
|] |> Array.filter id |> Array.length |> printfn "%d"