import java.util.*;
public class Main {
	public static void main(String args[]) {
		Scanner sc = new Scanner(System.in);
		int N = sc.nextInt();
		int d[] = new int[N];
		Map<Integer, Integer> map = new HashMap<Integer, Integer>();
		for(int i = 0; i < N; i++) {
			d[i] = sc.nextInt();
			map.put(d[i], 1);
		}
		System.out.println(map.size());
	}
} import java.util.*; util.* java public class Main {
	public static void main(String args[]) {
		Scanner sc = new Scanner(System.in);
		int N = sc.nextInt();
		int d[] = new int[N];
		Map<Integer, Integer> map = new HashMap<Integer, Integer>();
		for(int i = 0; i < N; i++) {
			d[i] = sc.nextInt();
			map.put(d[i], 1);
		}
		System.out.println(map.size());
	}
} Main public static void main(String args[]) {
		Scanner sc = new Scanner(System.in);
		int N = sc.nextInt();
		int d[] = new int[N];
		Map<Integer, Integer> map = new HashMap<Integer, Integer>();
		for(int i = 0; i < N; i++) {
			d[i] = sc.nextInt();
			map.put(d[i], 1);
		}
		System.out.println(map.size());
	} main {
		Scanner sc = new Scanner(System.in);
		int N = sc.nextInt();
		int d[] = new int[N];
		Map<Integer, Integer> map = new HashMap<Integer, Integer>();
		for(int i = 0; i < N; i++) {
			d[i] = sc.nextInt();
			map.put(d[i], 1);
		}
		System.out.println(map.size());
	} Scanner sc = new Scanner(System.in); sc new Scanner(System.in) int N = sc.nextInt(); N sc.nextInt() sc.nextInt sc int d[] = new int[N]; d new int[N] N Map<Integer, Integer> map = new HashMap<Integer, Integer>(); map new HashMap<Integer, Integer>() for(int i = 0; i < N; i++) {
			d[i] = sc.nextInt();
			map.put(d[i], 1);
		} int i = 0; int i = 0; i 0 i < N i N i++ i++ i {
			d[i] = sc.nextInt();
			map.put(d[i], 1);
		} {
			d[i] = sc.nextInt();
			map.put(d[i], 1);
		} d[i] = sc.nextInt() d[i] d i sc.nextInt() sc.nextInt sc map.put(d[i], 1) map.put map d[i] d i 1 System.out.println(map.size()) System.out.println System.out System System.out map.size() map.size map String args[] args public class Main {
	public static void main(String args[]) {
		Scanner sc = new Scanner(System.in);
		int N = sc.nextInt();
		int d[] = new int[N];
		Map<Integer, Integer> map = new HashMap<Integer, Integer>();
		for(int i = 0; i < N; i++) {
			d[i] = sc.nextInt();
			map.put(d[i], 1);
		}
		System.out.println(map.size());
	}
} public class Main {
	public static void main(String args[]) {
		Scanner sc = new Scanner(System.in);
		int N = sc.nextInt();
		int d[] = new int[N];
		Map<Integer, Integer> map = new HashMap<Integer, Integer>();
		for(int i = 0; i < N; i++) {
			d[i] = sc.nextInt();
			map.put(d[i], 1);
		}
		System.out.println(map.size());
	}
} Main
import java.util.*;
public class Main {
	public static void main(String args[]) {
		Scanner sc = new Scanner(System.in);
		int N = sc.nextInt();
		int d[] = new int[N];
		Map<Integer, Integer> map = new HashMap<Integer, Integer>();
		for(int i = 0; i < N; i++) {
			d[i] = sc.nextInt();
			map.put(d[i], 1);
		}
		System.out.println(map.size());
	}
}
