import java.util.*;

class Main{
    public static void main(String[] args){
        Scanner sc = new Scanner(System.in);
        HashSet<Integer> set = new HashSet<Integer>();
        int N = sc.nextInt();
        while(sc.hasNext()){
            set.add(sc.nextInt());
        }
        System.out.println(set.size());
    }
} import java.util.*; util.* java class Main{
    public static void main(String[] args){
        Scanner sc = new Scanner(System.in);
        HashSet<Integer> set = new HashSet<Integer>();
        int N = sc.nextInt();
        while(sc.hasNext()){
            set.add(sc.nextInt());
        }
        System.out.println(set.size());
    }
} Main public static void main(String[] args){
        Scanner sc = new Scanner(System.in);
        HashSet<Integer> set = new HashSet<Integer>();
        int N = sc.nextInt();
        while(sc.hasNext()){
            set.add(sc.nextInt());
        }
        System.out.println(set.size());
    } main {
        Scanner sc = new Scanner(System.in);
        HashSet<Integer> set = new HashSet<Integer>();
        int N = sc.nextInt();
        while(sc.hasNext()){
            set.add(sc.nextInt());
        }
        System.out.println(set.size());
    } Scanner sc = new Scanner(System.in); sc new Scanner(System.in) HashSet<Integer> set = new HashSet<Integer>(); set new HashSet<Integer>() int N = sc.nextInt(); N sc.nextInt() sc.nextInt sc while(sc.hasNext()){
            set.add(sc.nextInt());
        } sc.hasNext() sc.hasNext sc {
            set.add(sc.nextInt());
        } set.add(sc.nextInt()) set.add set sc.nextInt() sc.nextInt sc System.out.println(set.size()) System.out.println System.out System System.out set.size() set.size set String[] args args
import java.util.*;

class Main{
    public static void main(String[] args){
        Scanner sc = new Scanner(System.in);
        HashSet<Integer> set = new HashSet<Integer>();
        int N = sc.nextInt();
        while(sc.hasNext()){
            set.add(sc.nextInt());
        }
        System.out.println(set.size());
    }
}