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 = Integer.parseInt(sc.next());

        HashSet<Integer> list = new HashSet<>();
        for (int i = 0; i < n; i++) {
            list.add(Integer.parseInt(sc.next()));
        }
        System.out.print(list.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 = Integer.parseInt(sc.next());

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

        HashSet<Integer> list = new HashSet<>();
        for (int i = 0; i < n; i++) {
            list.add(Integer.parseInt(sc.next()));
        }
        System.out.print(list.size());
    } main {
        Scanner sc = new Scanner(System.in);
        int n = Integer.parseInt(sc.next());

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

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

        HashSet<Integer> list = new HashSet<>();
        for (int i = 0; i < n; i++) {
            list.add(Integer.parseInt(sc.next()));
        }
        System.out.print(list.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 = Integer.parseInt(sc.next());

        HashSet<Integer> list = new HashSet<>();
        for (int i = 0; i < n; i++) {
            list.add(Integer.parseInt(sc.next()));
        }
        System.out.print(list.size());
    }
}