import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.util.HashSet;
import java.util.Scanner;

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

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