import java.util.*;

public class Main {

	public static void main(String[] args) {

		//フィールド
		int n = 0;
		ArrayList<Integer> uniqueList = new ArrayList<Integer>();
		//リスト作成
		Scanner scanner = new Scanner(System.in);
		n = scanner.nextInt();
		ArrayList<Integer> intList = new ArrayList<Integer>();
		for(int i = 0; i < n; i++) {
			int x = scanner.nextInt();
			intList.add(x);
		}


		System.out.println(new HashSet<>(intList).size());
	}
} import java.util.*; util.* java public class Main {

	public static void main(String[] args) {

		//フィールド
		int n = 0;
		ArrayList<Integer> uniqueList = new ArrayList<Integer>();
		//リスト作成
		Scanner scanner = new Scanner(System.in);
		n = scanner.nextInt();
		ArrayList<Integer> intList = new ArrayList<Integer>();
		for(int i = 0; i < n; i++) {
			int x = scanner.nextInt();
			intList.add(x);
		}


		System.out.println(new HashSet<>(intList).size());
	}
} Main public static void main(String[] args) {

		//フィールド
		int n = 0;
		ArrayList<Integer> uniqueList = new ArrayList<Integer>();
		//リスト作成
		Scanner scanner = new Scanner(System.in);
		n = scanner.nextInt();
		ArrayList<Integer> intList = new ArrayList<Integer>();
		for(int i = 0; i < n; i++) {
			int x = scanner.nextInt();
			intList.add(x);
		}


		System.out.println(new HashSet<>(intList).size());
	} main {

		//フィールド
		int n = 0;
		ArrayList<Integer> uniqueList = new ArrayList<Integer>();
		//リスト作成
		Scanner scanner = new Scanner(System.in);
		n = scanner.nextInt();
		ArrayList<Integer> intList = new ArrayList<Integer>();
		for(int i = 0; i < n; i++) {
			int x = scanner.nextInt();
			intList.add(x);
		}


		System.out.println(new HashSet<>(intList).size());
	} int n = 0; n 0 ArrayList<Integer> uniqueList = new ArrayList<Integer>(); uniqueList new ArrayList<Integer>() Scanner scanner = new Scanner(System.in); scanner new Scanner(System.in) n = scanner.nextInt() n scanner.nextInt() scanner.nextInt scanner ArrayList<Integer> intList = new ArrayList<Integer>(); intList new ArrayList<Integer>() for(int i = 0; i < n; i++) {
			int x = scanner.nextInt();
			intList.add(x);
		} int i = 0; int i = 0; i 0 i < n i n i++ i++ i {
			int x = scanner.nextInt();
			intList.add(x);
		} {
			int x = scanner.nextInt();
			intList.add(x);
		} int x = scanner.nextInt(); x scanner.nextInt() scanner.nextInt scanner intList.add(x) intList.add intList x System.out.println(new HashSet<>(intList).size()) System.out.println System.out System System.out new HashSet<>(intList).size() new HashSet<>(intList).size new HashSet<>(intList) String[] args args public class Main {

	public static void main(String[] args) {

		//フィールド
		int n = 0;
		ArrayList<Integer> uniqueList = new ArrayList<Integer>();
		//リスト作成
		Scanner scanner = new Scanner(System.in);
		n = scanner.nextInt();
		ArrayList<Integer> intList = new ArrayList<Integer>();
		for(int i = 0; i < n; i++) {
			int x = scanner.nextInt();
			intList.add(x);
		}


		System.out.println(new HashSet<>(intList).size());
	}
} public class Main {

	public static void main(String[] args) {

		//フィールド
		int n = 0;
		ArrayList<Integer> uniqueList = new ArrayList<Integer>();
		//リスト作成
		Scanner scanner = new Scanner(System.in);
		n = scanner.nextInt();
		ArrayList<Integer> intList = new ArrayList<Integer>();
		for(int i = 0; i < n; i++) {
			int x = scanner.nextInt();
			intList.add(x);
		}


		System.out.println(new HashSet<>(intList).size());
	}
} Main
import java.util.*;

public class Main {

	public static void main(String[] args) {

		//フィールド
		int n = 0;
		ArrayList<Integer> uniqueList = new ArrayList<Integer>();
		//リスト作成
		Scanner scanner = new Scanner(System.in);
		n = scanner.nextInt();
		ArrayList<Integer> intList = new ArrayList<Integer>();
		for(int i = 0; i < n; i++) {
			int x = scanner.nextInt();
			intList.add(x);
		}


		System.out.println(new HashSet<>(intList).size());
	}
}
