import java.util.*;

public class Main {

    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);

        int N = scanner.nextInt();

        HashSet<Integer> hashSet = new HashSet<>();

        for(int i=0; i<N; i++){
            int d = scanner.nextInt();
            hashSet.add(d);
        }

        System.out.println(hashSet.size());


    }
} import java.util.*; util.* java public class Main {

    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);

        int N = scanner.nextInt();

        HashSet<Integer> hashSet = new HashSet<>();

        for(int i=0; i<N; i++){
            int d = scanner.nextInt();
            hashSet.add(d);
        }

        System.out.println(hashSet.size());


    }
} Main public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);

        int N = scanner.nextInt();

        HashSet<Integer> hashSet = new HashSet<>();

        for(int i=0; i<N; i++){
            int d = scanner.nextInt();
            hashSet.add(d);
        }

        System.out.println(hashSet.size());


    } main {
        Scanner scanner = new Scanner(System.in);

        int N = scanner.nextInt();

        HashSet<Integer> hashSet = new HashSet<>();

        for(int i=0; i<N; i++){
            int d = scanner.nextInt();
            hashSet.add(d);
        }

        System.out.println(hashSet.size());


    } Scanner scanner = new Scanner(System.in); scanner new Scanner(System.in) int N = scanner.nextInt(); N scanner.nextInt() scanner.nextInt scanner HashSet<Integer> hashSet = new HashSet<>(); hashSet new HashSet<>() for(int i=0; i<N; i++){
            int d = scanner.nextInt();
            hashSet.add(d);
        } int i=0; int i=0; i 0 i<N i N i++ i++ i {
            int d = scanner.nextInt();
            hashSet.add(d);
        } {
            int d = scanner.nextInt();
            hashSet.add(d);
        } int d = scanner.nextInt(); d scanner.nextInt() scanner.nextInt scanner hashSet.add(d) hashSet.add hashSet d System.out.println(hashSet.size()) System.out.println System.out System System.out hashSet.size() hashSet.size hashSet String[] args args public class Main {

    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);

        int N = scanner.nextInt();

        HashSet<Integer> hashSet = new HashSet<>();

        for(int i=0; i<N; i++){
            int d = scanner.nextInt();
            hashSet.add(d);
        }

        System.out.println(hashSet.size());


    }
} public class Main {

    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);

        int N = scanner.nextInt();

        HashSet<Integer> hashSet = new HashSet<>();

        for(int i=0; i<N; i++){
            int d = scanner.nextInt();
            hashSet.add(d);
        }

        System.out.println(hashSet.size());


    }
} Main
import java.util.*;

public class Main {

    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);

        int N = scanner.nextInt();

        HashSet<Integer> hashSet = new HashSet<>();

        for(int i=0; i<N; i++){
            int d = scanner.nextInt();
            hashSet.add(d);
        }

        System.out.println(hashSet.size());


    }
}
