import java.util.Arrays;
import java.util.HashSet;
import java.util.Scanner;
import java.util.Set;

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

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