import java.util.*;

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

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