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