import java.util.ArrayList;
import java.util.LinkedHashSet;
import java.util.Scanner;

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

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

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

    } main {
        Scanner scanner = new Scanner(System.in);
        int n = scanner.nextInt();
        ArrayList<Integer> num = new ArrayList<>();
        for (int i = 0; i < n; i++) {
            num.add(scanner.nextInt());
        }
        num = new ArrayList<Integer>(new LinkedHashSet<Integer>(num));
        System.out.println(num.size());

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

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

    }
} Main
import java.util.ArrayList;
import java.util.LinkedHashSet;
import java.util.Scanner;

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

    }
}