import java.util.*;

public class Main {

    public static void main(String[] args) {
        // write your code here
        Scanner sc = new Scanner(System.in);
        int n = Integer.parseInt(sc.next());
        Set<Integer> s = new HashSet<Integer>();
        for(int i = 0; i < n; i++)
        {
            int num = Integer.parseInt(sc.next());
            s.add(num);
        }
        
        System.out.println(s.size());
        sc.close();
    }
} import java.util.*; util.* java public class Main {

    public static void main(String[] args) {
        // write your code here
        Scanner sc = new Scanner(System.in);
        int n = Integer.parseInt(sc.next());
        Set<Integer> s = new HashSet<Integer>();
        for(int i = 0; i < n; i++)
        {
            int num = Integer.parseInt(sc.next());
            s.add(num);
        }
        
        System.out.println(s.size());
        sc.close();
    }
} Main public static void main(String[] args) {
        // write your code here
        Scanner sc = new Scanner(System.in);
        int n = Integer.parseInt(sc.next());
        Set<Integer> s = new HashSet<Integer>();
        for(int i = 0; i < n; i++)
        {
            int num = Integer.parseInt(sc.next());
            s.add(num);
        }
        
        System.out.println(s.size());
        sc.close();
    } main {
        // write your code here
        Scanner sc = new Scanner(System.in);
        int n = Integer.parseInt(sc.next());
        Set<Integer> s = new HashSet<Integer>();
        for(int i = 0; i < n; i++)
        {
            int num = Integer.parseInt(sc.next());
            s.add(num);
        }
        
        System.out.println(s.size());
        sc.close();
    } Scanner sc = new Scanner(System.in); sc new Scanner(System.in) int n = Integer.parseInt(sc.next()); n Integer.parseInt(sc.next()) Integer.parseInt Integer sc.next() sc.next sc Set<Integer> s = new HashSet<Integer>(); s new HashSet<Integer>() for(int i = 0; i < n; i++)
        {
            int num = Integer.parseInt(sc.next());
            s.add(num);
        } int i = 0; int i = 0; i 0 i < n i n i++ i++ i {
            int num = Integer.parseInt(sc.next());
            s.add(num);
        } {
            int num = Integer.parseInt(sc.next());
            s.add(num);
        } int num = Integer.parseInt(sc.next()); num Integer.parseInt(sc.next()) Integer.parseInt Integer sc.next() sc.next sc s.add(num) s.add s num System.out.println(s.size()) System.out.println System.out System System.out s.size() s.size s sc.close() sc.close sc String[] args args public class Main {

    public static void main(String[] args) {
        // write your code here
        Scanner sc = new Scanner(System.in);
        int n = Integer.parseInt(sc.next());
        Set<Integer> s = new HashSet<Integer>();
        for(int i = 0; i < n; i++)
        {
            int num = Integer.parseInt(sc.next());
            s.add(num);
        }
        
        System.out.println(s.size());
        sc.close();
    }
} public class Main {

    public static void main(String[] args) {
        // write your code here
        Scanner sc = new Scanner(System.in);
        int n = Integer.parseInt(sc.next());
        Set<Integer> s = new HashSet<Integer>();
        for(int i = 0; i < n; i++)
        {
            int num = Integer.parseInt(sc.next());
            s.add(num);
        }
        
        System.out.println(s.size());
        sc.close();
    }
} Main
import java.util.*;

public class Main {

    public static void main(String[] args) {
        // write your code here
        Scanner sc = new Scanner(System.in);
        int n = Integer.parseInt(sc.next());
        Set<Integer> s = new HashSet<Integer>();
        for(int i = 0; i < n; i++)
        {
            int num = Integer.parseInt(sc.next());
            s.add(num);
        }
        
        System.out.println(s.size());
        sc.close();
    }
}