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