import java.util.*;

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