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