import java.util.*;

class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        List<Integer> list = new ArrayList<>();
        for(int i = 0 ; i < n ; i ++){
          list.add(sc.nextInt());
        }
		 List<Integer> listB = new ArrayList<Integer>(new HashSet<>(list));
      
      	 System.out.print(listB.size());

    }
}



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

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

    } main {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        List<Integer> list = new ArrayList<>();
        for(int i = 0 ; i < n ; i ++){
          list.add(sc.nextInt());
        }
		 List<Integer> listB = new ArrayList<Integer>(new HashSet<>(list));
      
      	 System.out.print(listB.size());

    } Scanner sc = new Scanner(System.in); sc new Scanner(System.in) int n = sc.nextInt(); n sc.nextInt() sc.nextInt sc List<Integer> list = new ArrayList<>(); list new ArrayList<>() for(int i = 0 ; i < n ; i ++){
          list.add(sc.nextInt());
        } int i = 0 ; int i = 0 ; i 0 i < n i n 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 HashSet<>(list)); listB new ArrayList<Integer>(new HashSet<>(list)) System.out.print(listB.size()) System.out.print System.out System System.out listB.size() listB.size listB String[] args args
import java.util.*;

class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        List<Integer> list = new ArrayList<>();
        for(int i = 0 ; i < n ; i ++){
          list.add(sc.nextInt());
        }
		 List<Integer> listB = new ArrayList<Integer>(new HashSet<>(list));
      
      	 System.out.print(listB.size());

    }
}




