import java.util.*;

public class Main {

	public static void main(String... nui) {
		
		Scanner sc = new Scanner(System.in);
		
		Set<Integer> set = new HashSet<>();
		
		int n = sc.nextInt();
		
		for (int i = 0; i < n; i++) set.add(sc.nextInt());
		
		System.out.println(set.size());
		
	}

} import java.util.*; util.* java public class Main {

	public static void main(String... nui) {
		
		Scanner sc = new Scanner(System.in);
		
		Set<Integer> set = new HashSet<>();
		
		int n = sc.nextInt();
		
		for (int i = 0; i < n; i++) set.add(sc.nextInt());
		
		System.out.println(set.size());
		
	}

} Main public static void main(String... nui) {
		
		Scanner sc = new Scanner(System.in);
		
		Set<Integer> set = new HashSet<>();
		
		int n = sc.nextInt();
		
		for (int i = 0; i < n; i++) set.add(sc.nextInt());
		
		System.out.println(set.size());
		
	} main {
		
		Scanner sc = new Scanner(System.in);
		
		Set<Integer> set = new HashSet<>();
		
		int n = sc.nextInt();
		
		for (int i = 0; i < n; i++) set.add(sc.nextInt());
		
		System.out.println(set.size());
		
	} Scanner sc = new Scanner(System.in); sc new Scanner(System.in) Set<Integer> set = new HashSet<>(); set new HashSet<>() int n = sc.nextInt(); n sc.nextInt() sc.nextInt sc for (int i = 0; i < n; i++) set.add(sc.nextInt()); int i = 0; int i = 0; i 0 i < n i n i++ i++ i set.add(sc.nextInt()); set.add(sc.nextInt()) set.add set sc.nextInt() sc.nextInt sc System.out.println(set.size()) System.out.println System.out System System.out set.size() set.size set String... nui nui public class Main {

	public static void main(String... nui) {
		
		Scanner sc = new Scanner(System.in);
		
		Set<Integer> set = new HashSet<>();
		
		int n = sc.nextInt();
		
		for (int i = 0; i < n; i++) set.add(sc.nextInt());
		
		System.out.println(set.size());
		
	}

} public class Main {

	public static void main(String... nui) {
		
		Scanner sc = new Scanner(System.in);
		
		Set<Integer> set = new HashSet<>();
		
		int n = sc.nextInt();
		
		for (int i = 0; i < n; i++) set.add(sc.nextInt());
		
		System.out.println(set.size());
		
	}

} Main
import java.util.*;

public class Main {

	public static void main(String... nui) {
		
		Scanner sc = new Scanner(System.in);
		
		Set<Integer> set = new HashSet<>();
		
		int n = sc.nextInt();
		
		for (int i = 0; i < n; i++) set.add(sc.nextInt());
		
		System.out.println(set.size());
		
	}

}