import java.util.HashSet;
import java.util.Scanner;

public class Main {

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

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

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

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

public class Main {

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