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


public class Main {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int N;
		N = sc.nextInt();
		Set<Integer> set = new HashSet<Integer>();
		for(int i=0; i < N; ++i) {
			int s = sc.nextInt();
			set.add(s);
		}
		System.out.println(set.size());
	}
} import java.util.HashSet; HashSet java.util import java.util.Scanner; Scanner java.util import java.util.Set; Set java.util public class Main {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int N;
		N = sc.nextInt();
		Set<Integer> set = new HashSet<Integer>();
		for(int i=0; i < N; ++i) {
			int s = sc.nextInt();
			set.add(s);
		}
		System.out.println(set.size());
	}
} Main public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int N;
		N = sc.nextInt();
		Set<Integer> set = new HashSet<Integer>();
		for(int i=0; i < N; ++i) {
			int s = sc.nextInt();
			set.add(s);
		}
		System.out.println(set.size());
	} main {
		Scanner sc = new Scanner(System.in);
		int N;
		N = sc.nextInt();
		Set<Integer> set = new HashSet<Integer>();
		for(int i=0; i < N; ++i) {
			int s = sc.nextInt();
			set.add(s);
		}
		System.out.println(set.size());
	} Scanner sc = new Scanner(System.in); sc new Scanner(System.in) int N; N N = sc.nextInt() N sc.nextInt() sc.nextInt sc Set<Integer> set = new HashSet<Integer>(); set new HashSet<Integer>() for(int i=0; i < N; ++i) {
			int s = sc.nextInt();
			set.add(s);
		} int i=0; int i=0; i 0 i < N i N ++i ++i i {
			int s = sc.nextInt();
			set.add(s);
		} {
			int s = sc.nextInt();
			set.add(s);
		} int s = sc.nextInt(); s sc.nextInt() sc.nextInt sc set.add(s) set.add set s System.out.println(set.size()) System.out.println System.out System System.out set.size() set.size set String[] args args public class Main {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int N;
		N = sc.nextInt();
		Set<Integer> set = new HashSet<Integer>();
		for(int i=0; i < N; ++i) {
			int s = sc.nextInt();
			set.add(s);
		}
		System.out.println(set.size());
	}
} public class Main {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int N;
		N = sc.nextInt();
		Set<Integer> set = new HashSet<Integer>();
		for(int i=0; i < N; ++i) {
			int s = sc.nextInt();
			set.add(s);
		}
		System.out.println(set.size());
	}
} Main
import java.util.HashSet;
import java.util.Scanner;
import java.util.Set;


public class Main {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int N;
		N = sc.nextInt();
		Set<Integer> set = new HashSet<Integer>();
		for(int i=0; i < N; ++i) {
			int s = sc.nextInt();
			set.add(s);
		}
		System.out.println(set.size());
	}
}
