import java.util.HashSet;
import java.util.Scanner;
     
class Main{
    public static void main(String arg[]) {
        Scanner sc = new Scanner(System.in);
        int N = sc.nextInt();
        HashSet<Integer> hs = new HashSet<Integer>();

        for(int i = 0; i < N; i++) {
            hs.add(sc.nextInt());
        }

        sc.close();

        System.out.println(hs.size());    
    }
} import java.util.HashSet; HashSet java.util import java.util.Scanner; Scanner java.util class Main{
    public static void main(String arg[]) {
        Scanner sc = new Scanner(System.in);
        int N = sc.nextInt();
        HashSet<Integer> hs = new HashSet<Integer>();

        for(int i = 0; i < N; i++) {
            hs.add(sc.nextInt());
        }

        sc.close();

        System.out.println(hs.size());    
    }
} Main public static void main(String arg[]) {
        Scanner sc = new Scanner(System.in);
        int N = sc.nextInt();
        HashSet<Integer> hs = new HashSet<Integer>();

        for(int i = 0; i < N; i++) {
            hs.add(sc.nextInt());
        }

        sc.close();

        System.out.println(hs.size());    
    } main {
        Scanner sc = new Scanner(System.in);
        int N = sc.nextInt();
        HashSet<Integer> hs = new HashSet<Integer>();

        for(int i = 0; i < N; i++) {
            hs.add(sc.nextInt());
        }

        sc.close();

        System.out.println(hs.size());    
    } Scanner sc = new Scanner(System.in); sc new Scanner(System.in) int N = sc.nextInt(); N sc.nextInt() sc.nextInt sc HashSet<Integer> hs = new HashSet<Integer>(); hs new HashSet<Integer>() for(int i = 0; i < N; i++) {
            hs.add(sc.nextInt());
        } int i = 0; int i = 0; i 0 i < N i N i++ i++ i {
            hs.add(sc.nextInt());
        } {
            hs.add(sc.nextInt());
        } hs.add(sc.nextInt()) hs.add hs sc.nextInt() sc.nextInt sc sc.close() sc.close sc System.out.println(hs.size()) System.out.println System.out System System.out hs.size() hs.size hs String arg[] arg
import java.util.HashSet;
import java.util.Scanner;
     
class Main{
    public static void main(String arg[]) {
        Scanner sc = new Scanner(System.in);
        int N = sc.nextInt();
        HashSet<Integer> hs = new HashSet<Integer>();

        for(int i = 0; i < N; i++) {
            hs.add(sc.nextInt());
        }

        sc.close();

        System.out.println(hs.size());    
    }
}