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

public class Main {

	public static void main(String[] args) {

		Scanner sc = new Scanner(System.in);
		HashSet<Integer> h = new HashSet<Integer>();
		int n = sc.nextInt();
		for(int i = 0; i < n; i++) {
			h.add(sc.nextInt());
		}
		System.out.println(h.size());
		sc.close();
	}
} import java.util.HashSet; HashSet java.util import java.util.Scanner; Scanner java.util public class Main {

	public static void main(String[] args) {

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

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

		Scanner sc = new Scanner(System.in);
		HashSet<Integer> h = new HashSet<Integer>();
		int n = sc.nextInt();
		for(int i = 0; i < n; i++) {
			h.add(sc.nextInt());
		}
		System.out.println(h.size());
		sc.close();
	} Scanner sc = new Scanner(System.in); sc new Scanner(System.in) HashSet<Integer> h = new HashSet<Integer>(); h new HashSet<Integer>() int n = sc.nextInt(); n sc.nextInt() sc.nextInt sc for(int i = 0; i < n; i++) {
			h.add(sc.nextInt());
		} int i = 0; int i = 0; i 0 i < n i n i++ i++ i {
			h.add(sc.nextInt());
		} {
			h.add(sc.nextInt());
		} h.add(sc.nextInt()) h.add h sc.nextInt() sc.nextInt sc System.out.println(h.size()) System.out.println System.out System System.out h.size() h.size h sc.close() sc.close sc String[] args args public class Main {

	public static void main(String[] args) {

		Scanner sc = new Scanner(System.in);
		HashSet<Integer> h = new HashSet<Integer>();
		int n = sc.nextInt();
		for(int i = 0; i < n; i++) {
			h.add(sc.nextInt());
		}
		System.out.println(h.size());
		sc.close();
	}
} public class Main {

	public static void main(String[] args) {

		Scanner sc = new Scanner(System.in);
		HashSet<Integer> h = new HashSet<Integer>();
		int n = sc.nextInt();
		for(int i = 0; i < n; i++) {
			h.add(sc.nextInt());
		}
		System.out.println(h.size());
		sc.close();
	}
} Main
import java.util.HashSet;
import java.util.Scanner;

public class Main {

	public static void main(String[] args) {

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