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