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

public class Main {
    public static void main(String[] args) {
        HashSet<Integer> nums = new HashSet<>();
        HashSet<Integer> doubles = new HashSet<>();
        Scanner scanner = new Scanner(System.in);
        int N = scanner.nextInt();
        for (int i = 0; i < N; i++) {
            int v = scanner.nextInt();
            if (nums.contains(v)) {
                doubles.add(v);
            }
            nums.add(v);
        }
        System.out.println(nums.size() - doubles.size());


    }
}