import java.util.ArrayList;
import java.util.HashSet;
import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        String line = scanner.nextLine();
        String[] values = line.split(" ");
        long count = Integer.parseInt(values[0]);
        ArrayList<Long> l1 = new ArrayList<>();
        line = scanner.nextLine();
        values = line.split(" ");
        for (int i = 0; i < count; i++) {
            l1.add(Long.valueOf(values[i]));
        }
        HashSet<Long> s1 = new HashSet<>(l1);
        if (l1.size() == s1.size()) {
            System.out.println("YES");
        } else {
            System.out.println("NO");
        }
    }
} import java.util.ArrayList; ArrayList java.util import java.util.HashSet; HashSet java.util import java.util.Scanner; Scanner java.util public class Main {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        String line = scanner.nextLine();
        String[] values = line.split(" ");
        long count = Integer.parseInt(values[0]);
        ArrayList<Long> l1 = new ArrayList<>();
        line = scanner.nextLine();
        values = line.split(" ");
        for (int i = 0; i < count; i++) {
            l1.add(Long.valueOf(values[i]));
        }
        HashSet<Long> s1 = new HashSet<>(l1);
        if (l1.size() == s1.size()) {
            System.out.println("YES");
        } else {
            System.out.println("NO");
        }
    }
} Main public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        String line = scanner.nextLine();
        String[] values = line.split(" ");
        long count = Integer.parseInt(values[0]);
        ArrayList<Long> l1 = new ArrayList<>();
        line = scanner.nextLine();
        values = line.split(" ");
        for (int i = 0; i < count; i++) {
            l1.add(Long.valueOf(values[i]));
        }
        HashSet<Long> s1 = new HashSet<>(l1);
        if (l1.size() == s1.size()) {
            System.out.println("YES");
        } else {
            System.out.println("NO");
        }
    } main {
        Scanner scanner = new Scanner(System.in);
        String line = scanner.nextLine();
        String[] values = line.split(" ");
        long count = Integer.parseInt(values[0]);
        ArrayList<Long> l1 = new ArrayList<>();
        line = scanner.nextLine();
        values = line.split(" ");
        for (int i = 0; i < count; i++) {
            l1.add(Long.valueOf(values[i]));
        }
        HashSet<Long> s1 = new HashSet<>(l1);
        if (l1.size() == s1.size()) {
            System.out.println("YES");
        } else {
            System.out.println("NO");
        }
    } Scanner scanner = new Scanner(System.in); scanner new Scanner(System.in) String line = scanner.nextLine(); line scanner.nextLine() scanner.nextLine scanner String[] values = line.split(" "); values line.split(" ") line.split line " " long count = Integer.parseInt(values[0]); count Integer.parseInt(values[0]) Integer.parseInt Integer values[0] values 0 ArrayList<Long> l1 = new ArrayList<>(); l1 new ArrayList<>() line = scanner.nextLine() line scanner.nextLine() scanner.nextLine scanner values = line.split(" ") values line.split(" ") line.split line " " for (int i = 0; i < count; i++) {
            l1.add(Long.valueOf(values[i]));
        } int i = 0; int i = 0; i 0 i < count i count i++ i++ i {
            l1.add(Long.valueOf(values[i]));
        } {
            l1.add(Long.valueOf(values[i]));
        } l1.add(Long.valueOf(values[i])) l1.add l1 Long.valueOf(values[i]) Long.valueOf Long values[i] values i HashSet<Long> s1 = new HashSet<>(l1); s1 new HashSet<>(l1) if (l1.size() == s1.size()) {
            System.out.println("YES");
        } else {
            System.out.println("NO");
        } l1.size() == s1.size() l1.size() l1.size l1 s1.size() s1.size s1 {
            System.out.println("YES");
        } System.out.println("YES") System.out.println System.out System System.out "YES" {
            System.out.println("NO");
        } System.out.println("NO") System.out.println System.out System System.out "NO" String[] args args public class Main {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        String line = scanner.nextLine();
        String[] values = line.split(" ");
        long count = Integer.parseInt(values[0]);
        ArrayList<Long> l1 = new ArrayList<>();
        line = scanner.nextLine();
        values = line.split(" ");
        for (int i = 0; i < count; i++) {
            l1.add(Long.valueOf(values[i]));
        }
        HashSet<Long> s1 = new HashSet<>(l1);
        if (l1.size() == s1.size()) {
            System.out.println("YES");
        } else {
            System.out.println("NO");
        }
    }
} public class Main {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        String line = scanner.nextLine();
        String[] values = line.split(" ");
        long count = Integer.parseInt(values[0]);
        ArrayList<Long> l1 = new ArrayList<>();
        line = scanner.nextLine();
        values = line.split(" ");
        for (int i = 0; i < count; i++) {
            l1.add(Long.valueOf(values[i]));
        }
        HashSet<Long> s1 = new HashSet<>(l1);
        if (l1.size() == s1.size()) {
            System.out.println("YES");
        } else {
            System.out.println("NO");
        }
    }
} Main
import java.util.ArrayList;
import java.util.HashSet;
import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        String line = scanner.nextLine();
        String[] values = line.split(" ");
        long count = Integer.parseInt(values[0]);
        ArrayList<Long> l1 = new ArrayList<>();
        line = scanner.nextLine();
        values = line.split(" ");
        for (int i = 0; i < count; i++) {
            l1.add(Long.valueOf(values[i]));
        }
        HashSet<Long> s1 = new HashSet<>(l1);
        if (l1.size() == s1.size()) {
            System.out.println("YES");
        } else {
            System.out.println("NO");
        }
    }
}