import java.util.*;
public class Main {
	
	public static void main (String[]args) {
		Scanner sc = new Scanner(System.in);
		
		int N =  sc.nextInt();

        List<Integer>inputList = new ArrayList<Integer>();
        // 入力値分入力を求める	
		for (int i = 0; i < N;i++) {
		
			int num = sc.nextInt();
		
			inputList.add(num);
		}

        // 入力値の重複を削除
         List<Integer> listB = new ArrayList<Integer>(new HashSet<>(inputList));
		
        // 要素数を出力
        System.out.println(listB.size());
	}	


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

        List<Integer>inputList = new ArrayList<Integer>();
        // 入力値分入力を求める	
		for (int i = 0; i < N;i++) {
		
			int num = sc.nextInt();
		
			inputList.add(num);
		}

        // 入力値の重複を削除
         List<Integer> listB = new ArrayList<Integer>(new HashSet<>(inputList));
		
        // 要素数を出力
        System.out.println(listB.size());
	}	


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

        List<Integer>inputList = new ArrayList<Integer>();
        // 入力値分入力を求める	
		for (int i = 0; i < N;i++) {
		
			int num = sc.nextInt();
		
			inputList.add(num);
		}

        // 入力値の重複を削除
         List<Integer> listB = new ArrayList<Integer>(new HashSet<>(inputList));
		
        // 要素数を出力
        System.out.println(listB.size());
	} main {
		Scanner sc = new Scanner(System.in);
		
		int N =  sc.nextInt();

        List<Integer>inputList = new ArrayList<Integer>();
        // 入力値分入力を求める	
		for (int i = 0; i < N;i++) {
		
			int num = sc.nextInt();
		
			inputList.add(num);
		}

        // 入力値の重複を削除
         List<Integer> listB = new ArrayList<Integer>(new HashSet<>(inputList));
		
        // 要素数を出力
        System.out.println(listB.size());
	} Scanner sc = new Scanner(System.in); sc new Scanner(System.in) int N =  sc.nextInt(); N sc.nextInt() sc.nextInt sc List<Integer>inputList = new ArrayList<Integer>(); inputList new ArrayList<Integer>() for (int i = 0; i < N;i++) {
		
			int num = sc.nextInt();
		
			inputList.add(num);
		} int i = 0; int i = 0; i 0 i < N i N i++ i++ i {
		
			int num = sc.nextInt();
		
			inputList.add(num);
		} {
		
			int num = sc.nextInt();
		
			inputList.add(num);
		} int num = sc.nextInt(); num sc.nextInt() sc.nextInt sc inputList.add(num) inputList.add inputList num List<Integer> listB = new ArrayList<Integer>(new HashSet<>(inputList)); listB new ArrayList<Integer>(new HashSet<>(inputList)) System.out.println(listB.size()) System.out.println System.out System System.out listB.size() listB.size listB String[]args args public class Main {
	
	public static void main (String[]args) {
		Scanner sc = new Scanner(System.in);
		
		int N =  sc.nextInt();

        List<Integer>inputList = new ArrayList<Integer>();
        // 入力値分入力を求める	
		for (int i = 0; i < N;i++) {
		
			int num = sc.nextInt();
		
			inputList.add(num);
		}

        // 入力値の重複を削除
         List<Integer> listB = new ArrayList<Integer>(new HashSet<>(inputList));
		
        // 要素数を出力
        System.out.println(listB.size());
	}	


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

        List<Integer>inputList = new ArrayList<Integer>();
        // 入力値分入力を求める	
		for (int i = 0; i < N;i++) {
		
			int num = sc.nextInt();
		
			inputList.add(num);
		}

        // 入力値の重複を削除
         List<Integer> listB = new ArrayList<Integer>(new HashSet<>(inputList));
		
        // 要素数を出力
        System.out.println(listB.size());
	}	


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

        List<Integer>inputList = new ArrayList<Integer>();
        // 入力値分入力を求める	
		for (int i = 0; i < N;i++) {
		
			int num = sc.nextInt();
		
			inputList.add(num);
		}

        // 入力値の重複を削除
         List<Integer> listB = new ArrayList<Integer>(new HashSet<>(inputList));
		
        // 要素数を出力
        System.out.println(listB.size());
	}	


}