import java.util.*;
public class Main {
  public static void main(String[] args){
    Scanner sc = new Scanner(System.in);
    int num = sc.nextInt();
	ArrayList<Integer> list = new ArrayList<>();
	for(int i=0; i<num; i++){
		list.add(sc.nextInt());
	}
	List<Integer> listB = new ArrayList<Integer>(new LinkedHashSet<>(list));
	System.out.println(listB.size());
  }
} import java.util.*; util.* java public class Main {
  public static void main(String[] args){
    Scanner sc = new Scanner(System.in);
    int num = sc.nextInt();
	ArrayList<Integer> list = new ArrayList<>();
	for(int i=0; i<num; i++){
		list.add(sc.nextInt());
	}
	List<Integer> listB = new ArrayList<Integer>(new LinkedHashSet<>(list));
	System.out.println(listB.size());
  }
} Main public static void main(String[] args){
    Scanner sc = new Scanner(System.in);
    int num = sc.nextInt();
	ArrayList<Integer> list = new ArrayList<>();
	for(int i=0; i<num; i++){
		list.add(sc.nextInt());
	}
	List<Integer> listB = new ArrayList<Integer>(new LinkedHashSet<>(list));
	System.out.println(listB.size());
  } main {
    Scanner sc = new Scanner(System.in);
    int num = sc.nextInt();
	ArrayList<Integer> list = new ArrayList<>();
	for(int i=0; i<num; i++){
		list.add(sc.nextInt());
	}
	List<Integer> listB = new ArrayList<Integer>(new LinkedHashSet<>(list));
	System.out.println(listB.size());
  } Scanner sc = new Scanner(System.in); sc new Scanner(System.in) int num = sc.nextInt(); num sc.nextInt() sc.nextInt sc ArrayList<Integer> list = new ArrayList<>(); list new ArrayList<>() for(int i=0; i<num; i++){
		list.add(sc.nextInt());
	} int i=0; int i=0; i 0 i<num i num i++ i++ i {
		list.add(sc.nextInt());
	} {
		list.add(sc.nextInt());
	} list.add(sc.nextInt()) list.add list sc.nextInt() sc.nextInt sc List<Integer> listB = new ArrayList<Integer>(new LinkedHashSet<>(list)); listB new ArrayList<Integer>(new LinkedHashSet<>(list)) System.out.println(listB.size()) System.out.println System.out System System.out listB.size() listB.size listB String[] args args public class Main {
  public static void main(String[] args){
    Scanner sc = new Scanner(System.in);
    int num = sc.nextInt();
	ArrayList<Integer> list = new ArrayList<>();
	for(int i=0; i<num; i++){
		list.add(sc.nextInt());
	}
	List<Integer> listB = new ArrayList<Integer>(new LinkedHashSet<>(list));
	System.out.println(listB.size());
  }
} public class Main {
  public static void main(String[] args){
    Scanner sc = new Scanner(System.in);
    int num = sc.nextInt();
	ArrayList<Integer> list = new ArrayList<>();
	for(int i=0; i<num; i++){
		list.add(sc.nextInt());
	}
	List<Integer> listB = new ArrayList<Integer>(new LinkedHashSet<>(list));
	System.out.println(listB.size());
  }
} Main
import java.util.*;
public class Main {
  public static void main(String[] args){
    Scanner sc = new Scanner(System.in);
    int num = sc.nextInt();
	ArrayList<Integer> list = new ArrayList<>();
	for(int i=0; i<num; i++){
		list.add(sc.nextInt());
	}
	List<Integer> listB = new ArrayList<Integer>(new LinkedHashSet<>(list));
	System.out.println(listB.size());
  }
}