import java.util.*;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import java.util.Scanner;
import java.util.HashSet;

public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);

        int n = sc.nextInt();
        List<Integer> d = new ArrayList<>();
        for (int i = 0; i < n; i++) {
            d.add(sc.nextInt());
        }
        List<Integer> d_new = new ArrayList<>(new HashSet<>(d));
        System.out.println(d_new.size());
    }
}


 import java.util.*; util.* java import java.util.ArrayList; ArrayList java.util import java.util.Arrays; Arrays java.util import java.util.List; List java.util import java.util.Scanner; Scanner java.util import java.util.HashSet; HashSet java.util public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);

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

        int n = sc.nextInt();
        List<Integer> d = new ArrayList<>();
        for (int i = 0; i < n; i++) {
            d.add(sc.nextInt());
        }
        List<Integer> d_new = new ArrayList<>(new HashSet<>(d));
        System.out.println(d_new.size());
    } main {
        Scanner sc = new Scanner(System.in);

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

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

        int n = sc.nextInt();
        List<Integer> d = new ArrayList<>();
        for (int i = 0; i < n; i++) {
            d.add(sc.nextInt());
        }
        List<Integer> d_new = new ArrayList<>(new HashSet<>(d));
        System.out.println(d_new.size());
    }
} Main
import java.util.*;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import java.util.Scanner;
import java.util.HashSet;

public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);

        int n = sc.nextInt();
        List<Integer> d = new ArrayList<>();
        for (int i = 0; i < n; i++) {
            d.add(sc.nextInt());
        }
        List<Integer> d_new = new ArrayList<>(new HashSet<>(d));
        System.out.println(d_new.size());
    }
}



