import java.util.*;

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