import java.util.*;

public class Main {
    static Scanner scanner = new Scanner(System.in);

    public static void main(String[]$) {
        int n = scanner.nextInt();
        Set<Integer> set = new HashSet<>();
        for (int i = 0; i < n; i++) {
            set.add(scanner.nextInt());
        }
        System.out.println(set.size());
    }
} import java.util.*; util.* java public class Main {
    static Scanner scanner = new Scanner(System.in);

    public static void main(String[]$) {
        int n = scanner.nextInt();
        Set<Integer> set = new HashSet<>();
        for (int i = 0; i < n; i++) {
            set.add(scanner.nextInt());
        }
        System.out.println(set.size());
    }
} Main static Scanner scanner = new Scanner(System.in); scanner new Scanner(System.in) public static void main(String[]$) {
        int n = scanner.nextInt();
        Set<Integer> set = new HashSet<>();
        for (int i = 0; i < n; i++) {
            set.add(scanner.nextInt());
        }
        System.out.println(set.size());
    } main {
        int n = scanner.nextInt();
        Set<Integer> set = new HashSet<>();
        for (int i = 0; i < n; i++) {
            set.add(scanner.nextInt());
        }
        System.out.println(set.size());
    } int n = scanner.nextInt(); n scanner.nextInt() scanner.nextInt scanner Set<Integer> set = new HashSet<>(); set new HashSet<>() for (int i = 0; i < n; i++) {
            set.add(scanner.nextInt());
        } int i = 0; int i = 0; i 0 i < n i n i++ i++ i {
            set.add(scanner.nextInt());
        } {
            set.add(scanner.nextInt());
        } set.add(scanner.nextInt()) set.add set scanner.nextInt() scanner.nextInt scanner System.out.println(set.size()) System.out.println System.out System System.out set.size() set.size set String[]$ $ public class Main {
    static Scanner scanner = new Scanner(System.in);

    public static void main(String[]$) {
        int n = scanner.nextInt();
        Set<Integer> set = new HashSet<>();
        for (int i = 0; i < n; i++) {
            set.add(scanner.nextInt());
        }
        System.out.println(set.size());
    }
} public class Main {
    static Scanner scanner = new Scanner(System.in);

    public static void main(String[]$) {
        int n = scanner.nextInt();
        Set<Integer> set = new HashSet<>();
        for (int i = 0; i < n; i++) {
            set.add(scanner.nextInt());
        }
        System.out.println(set.size());
    }
} Main
import java.util.*;

public class Main {
    static Scanner scanner = new Scanner(System.in);

    public static void main(String[]$) {
        int n = scanner.nextInt();
        Set<Integer> set = new HashSet<>();
        for (int i = 0; i < n; i++) {
            set.add(scanner.nextInt());
        }
        System.out.println(set.size());
    }
}