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