import java.util.Scanner;
class Main{
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		Boolean [] flug = new Boolean [1000001];
		
		int num = sc.nextInt();int count = 0;
		
		for(int i = 0; i < flug.length ; i++) flug[i] = false;
		
		for(int i = 0; i < num ; i++) {
			int t = sc.nextInt();
			if(flug[t] == false) {
				flug[t] = true;
				count++;
			}
		}
		System.out.println(count);
	}
}