import java.util.*;

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

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