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

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

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