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

public class Main {
	public static void main(String[] args) {
		new Main().solve();
		return;
	}

	private void solve() {
		// 入力
		Scanner sc = new Scanner(System.in);
		int N = sc.nextInt();
		Set<Integer> d = new HashSet<Integer>();
		for (int i = 0; i < N; i++) {
			d.add(sc.nextInt());
		}
		sc.close();

		// 出力
		System.out.println(d.size());

		return;
	}
} 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) {
		new Main().solve();
		return;
	}

	private void solve() {
		// 入力
		Scanner sc = new Scanner(System.in);
		int N = sc.nextInt();
		Set<Integer> d = new HashSet<Integer>();
		for (int i = 0; i < N; i++) {
			d.add(sc.nextInt());
		}
		sc.close();

		// 出力
		System.out.println(d.size());

		return;
	}
} Main public static void main(String[] args) {
		new Main().solve();
		return;
	} main {
		new Main().solve();
		return;
	} new Main().solve() new Main().solve new Main() return; String[] args args private void solve() {
		// 入力
		Scanner sc = new Scanner(System.in);
		int N = sc.nextInt();
		Set<Integer> d = new HashSet<Integer>();
		for (int i = 0; i < N; i++) {
			d.add(sc.nextInt());
		}
		sc.close();

		// 出力
		System.out.println(d.size());

		return;
	} solve {
		// 入力
		Scanner sc = new Scanner(System.in);
		int N = sc.nextInt();
		Set<Integer> d = new HashSet<Integer>();
		for (int i = 0; i < N; i++) {
			d.add(sc.nextInt());
		}
		sc.close();

		// 出力
		System.out.println(d.size());

		return;
	} 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<Integer>(); d new HashSet<Integer>() 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(sc.nextInt()) d.add d sc.nextInt() sc.nextInt sc sc.close() sc.close sc System.out.println(d.size()) System.out.println System.out System System.out d.size() d.size d return; public class Main {
	public static void main(String[] args) {
		new Main().solve();
		return;
	}

	private void solve() {
		// 入力
		Scanner sc = new Scanner(System.in);
		int N = sc.nextInt();
		Set<Integer> d = new HashSet<Integer>();
		for (int i = 0; i < N; i++) {
			d.add(sc.nextInt());
		}
		sc.close();

		// 出力
		System.out.println(d.size());

		return;
	}
} public class Main {
	public static void main(String[] args) {
		new Main().solve();
		return;
	}

	private void solve() {
		// 入力
		Scanner sc = new Scanner(System.in);
		int N = sc.nextInt();
		Set<Integer> d = new HashSet<Integer>();
		for (int i = 0; i < N; i++) {
			d.add(sc.nextInt());
		}
		sc.close();

		// 出力
		System.out.println(d.size());

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

public class Main {
	public static void main(String[] args) {
		new Main().solve();
		return;
	}

	private void solve() {
		// 入力
		Scanner sc = new Scanner(System.in);
		int N = sc.nextInt();
		Set<Integer> d = new HashSet<Integer>();
		for (int i = 0; i < N; i++) {
			d.add(sc.nextInt());
		}
		sc.close();

		// 出力
		System.out.println(d.size());

		return;
	}
}