import java.util.HashMap;
import java.util.Scanner;

public class Main {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int N = sc.nextInt();

		HashMap<Integer, Integer> hMap = new HashMap<Integer, Integer>();
		for (int i=0; i<N; i++) {
			hMap.put(sc.nextInt(), 1) ;
		}
		System.out.println(hMap.size());


	}

} import java.util.HashMap; HashMap 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();

		HashMap<Integer, Integer> hMap = new HashMap<Integer, Integer>();
		for (int i=0; i<N; i++) {
			hMap.put(sc.nextInt(), 1) ;
		}
		System.out.println(hMap.size());


	}

} Main public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int N = sc.nextInt();

		HashMap<Integer, Integer> hMap = new HashMap<Integer, Integer>();
		for (int i=0; i<N; i++) {
			hMap.put(sc.nextInt(), 1) ;
		}
		System.out.println(hMap.size());


	} main {
		Scanner sc = new Scanner(System.in);
		int N = sc.nextInt();

		HashMap<Integer, Integer> hMap = new HashMap<Integer, Integer>();
		for (int i=0; i<N; i++) {
			hMap.put(sc.nextInt(), 1) ;
		}
		System.out.println(hMap.size());


	} Scanner sc = new Scanner(System.in); sc new Scanner(System.in) int N = sc.nextInt(); N sc.nextInt() sc.nextInt sc HashMap<Integer, Integer> hMap = new HashMap<Integer, Integer>(); hMap new HashMap<Integer, Integer>() for (int i=0; i<N; i++) {
			hMap.put(sc.nextInt(), 1) ;
		} int i=0; int i=0; i 0 i<N i N i++ i++ i {
			hMap.put(sc.nextInt(), 1) ;
		} {
			hMap.put(sc.nextInt(), 1) ;
		} hMap.put(sc.nextInt(), 1) hMap.put hMap sc.nextInt() sc.nextInt sc 1 System.out.println(hMap.size()) System.out.println System.out System System.out hMap.size() hMap.size hMap String[] args args public class Main {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int N = sc.nextInt();

		HashMap<Integer, Integer> hMap = new HashMap<Integer, Integer>();
		for (int i=0; i<N; i++) {
			hMap.put(sc.nextInt(), 1) ;
		}
		System.out.println(hMap.size());


	}

} public class Main {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int N = sc.nextInt();

		HashMap<Integer, Integer> hMap = new HashMap<Integer, Integer>();
		for (int i=0; i<N; i++) {
			hMap.put(sc.nextInt(), 1) ;
		}
		System.out.println(hMap.size());


	}

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

public class Main {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int N = sc.nextInt();

		HashMap<Integer, Integer> hMap = new HashMap<Integer, Integer>();
		for (int i=0; i<N; i++) {
			hMap.put(sc.nextInt(), 1) ;
		}
		System.out.println(hMap.size());


	}

}
