import java.util.ArrayList;
import java.util.Collections;
import java.util.Comparator;
import java.util.HashSet;
import java.util.List;
import java.util.Scanner;

public class Main {

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

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

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

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

public class Main {

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