import java.util.Scanner;

public class Main
{
    private final static Main main = new Main();

    public static void main(String[] args)
    {
        long l = System.currentTimeMillis();
        main.solve();
        //System.out.println("処理時間：" + (System.currentTimeMillis() - l));
    }

    private void solve()
    {
        Scanner sc = new Scanner(System.in);
        sc.nextLine();
        String s = sc.nextLine();
        String[] list = s.split(" ");
        for(String number : list)
        {
            if(s.indexOf(number) != s.lastIndexOf(number))
            {
                s = s.replace(number, "NULL");
            }
        }
        int ans = 0;
        String[] newList = s.split(" ");
        for(String item : newList)
        {
            if(!item.equals("NULL"))
            {
                ++ans;
            }
        }
        System.out.println(ans);
    }
}