import java.util.*;

public class Main {

    public static void main(String[] args) {
        // write your code here
        Scanner s = new Scanner(System.in);
        int n = Integer.parseInt(s.next());
        List<Integer> d = new ArrayList<Integer>();
        for(int i = 0; i < n; i++)
        {
            int num = Integer.parseInt(s.next());
            d.add(num);
        }

        Set<Integer> set = new HashSet<Integer>();
        for(int num : d) set.add(num);

        System.out.println(set.size());
        s.close();
    }
} import java.util.*; util.* java public class Main {

    public static void main(String[] args) {
        // write your code here
        Scanner s = new Scanner(System.in);
        int n = Integer.parseInt(s.next());
        List<Integer> d = new ArrayList<Integer>();
        for(int i = 0; i < n; i++)
        {
            int num = Integer.parseInt(s.next());
            d.add(num);
        }

        Set<Integer> set = new HashSet<Integer>();
        for(int num : d) set.add(num);

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

        Set<Integer> set = new HashSet<Integer>();
        for(int num : d) set.add(num);

        System.out.println(set.size());
        s.close();
    } main {
        // write your code here
        Scanner s = new Scanner(System.in);
        int n = Integer.parseInt(s.next());
        List<Integer> d = new ArrayList<Integer>();
        for(int i = 0; i < n; i++)
        {
            int num = Integer.parseInt(s.next());
            d.add(num);
        }

        Set<Integer> set = new HashSet<Integer>();
        for(int num : d) set.add(num);

        System.out.println(set.size());
        s.close();
    } Scanner s = new Scanner(System.in); s new Scanner(System.in) int n = Integer.parseInt(s.next()); n Integer.parseInt(s.next()) Integer.parseInt Integer s.next() s.next s List<Integer> d = new ArrayList<Integer>(); d new ArrayList<Integer>() for(int i = 0; i < n; i++)
        {
            int num = Integer.parseInt(s.next());
            d.add(num);
        } int i = 0; int i = 0; i 0 i < n i n i++ i++ i {
            int num = Integer.parseInt(s.next());
            d.add(num);
        } {
            int num = Integer.parseInt(s.next());
            d.add(num);
        } int num = Integer.parseInt(s.next()); num Integer.parseInt(s.next()) Integer.parseInt Integer s.next() s.next s d.add(num) d.add d num Set<Integer> set = new HashSet<Integer>(); set new HashSet<Integer>() for(int num : d) set.add(num); int num d set.add(num); set.add(num) set.add set num System.out.println(set.size()) System.out.println System.out System System.out set.size() set.size set s.close() s.close s String[] args args public class Main {

    public static void main(String[] args) {
        // write your code here
        Scanner s = new Scanner(System.in);
        int n = Integer.parseInt(s.next());
        List<Integer> d = new ArrayList<Integer>();
        for(int i = 0; i < n; i++)
        {
            int num = Integer.parseInt(s.next());
            d.add(num);
        }

        Set<Integer> set = new HashSet<Integer>();
        for(int num : d) set.add(num);

        System.out.println(set.size());
        s.close();
    }
} public class Main {

    public static void main(String[] args) {
        // write your code here
        Scanner s = new Scanner(System.in);
        int n = Integer.parseInt(s.next());
        List<Integer> d = new ArrayList<Integer>();
        for(int i = 0; i < n; i++)
        {
            int num = Integer.parseInt(s.next());
            d.add(num);
        }

        Set<Integer> set = new HashSet<Integer>();
        for(int num : d) set.add(num);

        System.out.println(set.size());
        s.close();
    }
} Main
import java.util.*;

public class Main {

    public static void main(String[] args) {
        // write your code here
        Scanner s = new Scanner(System.in);
        int n = Integer.parseInt(s.next());
        List<Integer> d = new ArrayList<Integer>();
        for(int i = 0; i < n; i++)
        {
            int num = Integer.parseInt(s.next());
            d.add(num);
        }

        Set<Integer> set = new HashSet<Integer>();
        for(int num : d) set.add(num);

        System.out.println(set.size());
        s.close();
    }
}
