package week02;

import java.util.*;

public class 明明的随机数 {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int m = sc.nextInt();

        Set hashSet = new HashSet<>();
        int []arr=new int [m];
        for(int j = 0; j < m; j ++)
        {
            arr[j] = sc.nextInt();
        }
        for(int i = 0; i < arr.length;  i++)
        {
            hashSet.add(arr[i]);
        }
        System.out.println(hashSet.size());

        TreeSet treeSet = new TreeSet();

        treeSet.addAll(hashSet);

            }
}