import java.util.HashSet;
import java.util.Scanner;

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

		System.out.println(set.size());
		reader.close();
	}


}


 import java.util.HashSet; HashSet java.util import java.util.Scanner; Scanner java.util public class Main {
	public static void main(String[] args) {
		Scanner reader = new Scanner(System.in);
		int N =  reader.nextInt();
		HashSet<Integer> set = new HashSet<Integer>();
		for (int i = 0; i < N; i++) {
			set.add(reader.nextInt());
		}

		System.out.println(set.size());
		reader.close();
	}


} Main public static void main(String[] args) {
		Scanner reader = new Scanner(System.in);
		int N =  reader.nextInt();
		HashSet<Integer> set = new HashSet<Integer>();
		for (int i = 0; i < N; i++) {
			set.add(reader.nextInt());
		}

		System.out.println(set.size());
		reader.close();
	} main {
		Scanner reader = new Scanner(System.in);
		int N =  reader.nextInt();
		HashSet<Integer> set = new HashSet<Integer>();
		for (int i = 0; i < N; i++) {
			set.add(reader.nextInt());
		}

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

		System.out.println(set.size());
		reader.close();
	}


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

		System.out.println(set.size());
		reader.close();
	}


} Main
import java.util.HashSet;
import java.util.Scanner;

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

		System.out.println(set.size());
		reader.close();
	}


}



