
import java.util.HashSet;
import java.util.Scanner;
import java.util.Set;

public class Main {
	public static void main(String[] args) {

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

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

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

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

		Scanner scan = new Scanner(System.in);
		int n = scan.nextInt();
		Set<Integer> set = new HashSet<>();
		
		for (int i = 0; i < n; i++) {
			set.add(scan.nextInt());
		}
		
		System.out.println(set.size());
	}
} Main

import java.util.HashSet;
import java.util.Scanner;
import java.util.Set;

public class Main {
	public static void main(String[] args) {

		Scanner scan = new Scanner(System.in);
		int n = scan.nextInt();
		Set<Integer> set = new HashSet<>();
		
		for (int i = 0; i < n; i++) {
			set.add(scan.nextInt());
		}
		
		System.out.println(set.size());
	}
}
