import java.util.*;

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

		int N = sc.nextInt();

		Set<Integer> d = new HashSet<>();

		for(int i=0; i<N; i++)
			d.add(sc.nextInt());

		println(d.size());

	}

	public static void print(Object o) {
		System.out.print(o);
	}

	public static void println(Object o) {
		System.out.println(o);
	}
} import java.util.*; util.* java public class Main {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);

		int N = sc.nextInt();

		Set<Integer> d = new HashSet<>();

		for(int i=0; i<N; i++)
			d.add(sc.nextInt());

		println(d.size());

	}

	public static void print(Object o) {
		System.out.print(o);
	}

	public static void println(Object o) {
		System.out.println(o);
	}
} Main public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);

		int N = sc.nextInt();

		Set<Integer> d = new HashSet<>();

		for(int i=0; i<N; i++)
			d.add(sc.nextInt());

		println(d.size());

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

		int N = sc.nextInt();

		Set<Integer> d = new HashSet<>();

		for(int i=0; i<N; i++)
			d.add(sc.nextInt());

		println(d.size());

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

		int N = sc.nextInt();

		Set<Integer> d = new HashSet<>();

		for(int i=0; i<N; i++)
			d.add(sc.nextInt());

		println(d.size());

	}

	public static void print(Object o) {
		System.out.print(o);
	}

	public static void println(Object o) {
		System.out.println(o);
	}
} public class Main {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);

		int N = sc.nextInt();

		Set<Integer> d = new HashSet<>();

		for(int i=0; i<N; i++)
			d.add(sc.nextInt());

		println(d.size());

	}

	public static void print(Object o) {
		System.out.print(o);
	}

	public static void println(Object o) {
		System.out.println(o);
	}
} Main
import java.util.*;

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

		int N = sc.nextInt();

		Set<Integer> d = new HashSet<>();

		for(int i=0; i<N; i++)
			d.add(sc.nextInt());

		println(d.size());

	}

	public static void print(Object o) {
		System.out.print(o);
	}

	public static void println(Object o) {
		System.out.println(o);
	}
}