open System
let readInt () = stdin.ReadLine() |> int
let readIntArray () = stdin.ReadLine().Split(' ') |> Array.map int

let N = readInt ()
let A : int [] = Array.zeroCreate N
for i in [0..N-1] do A.[i] <- readInt ()

A
|> Array.distinct
|> Array.length
|> printfn "%d"
