import java.util.*;

public class Main {
    public static void main(String[] args) throws Exception {
        Scanner sc = new Scanner(System.in);
        int N = Integer.parseInt(sc.next());
        List<Integer> numList = new ArrayList<>();
        for(int i=0;i<N;i++){
            numList.add(Integer.parseInt(sc.next()));
        }
        long count = numList.stream().distinct().count();
        String str = N == count ? "YES" : "NO";
        System.out.println(str);
}
} import java.util.*; util.* java public class Main {
    public static void main(String[] args) throws Exception {
        Scanner sc = new Scanner(System.in);
        int N = Integer.parseInt(sc.next());
        List<Integer> numList = new ArrayList<>();
        for(int i=0;i<N;i++){
            numList.add(Integer.parseInt(sc.next()));
        }
        long count = numList.stream().distinct().count();
        String str = N == count ? "YES" : "NO";
        System.out.println(str);
}
} Main public static void main(String[] args) throws Exception {
        Scanner sc = new Scanner(System.in);
        int N = Integer.parseInt(sc.next());
        List<Integer> numList = new ArrayList<>();
        for(int i=0;i<N;i++){
            numList.add(Integer.parseInt(sc.next()));
        }
        long count = numList.stream().distinct().count();
        String str = N == count ? "YES" : "NO";
        System.out.println(str);
} main {
        Scanner sc = new Scanner(System.in);
        int N = Integer.parseInt(sc.next());
        List<Integer> numList = new ArrayList<>();
        for(int i=0;i<N;i++){
            numList.add(Integer.parseInt(sc.next()));
        }
        long count = numList.stream().distinct().count();
        String str = N == count ? "YES" : "NO";
        System.out.println(str);
} Scanner sc = new Scanner(System.in); sc new Scanner(System.in) int N = Integer.parseInt(sc.next()); N Integer.parseInt(sc.next()) Integer.parseInt Integer sc.next() sc.next sc List<Integer> numList = new ArrayList<>(); numList new ArrayList<>() for(int i=0;i<N;i++){
            numList.add(Integer.parseInt(sc.next()));
        } int i=0; int i=0; i 0 i<N i N i++ i++ i {
            numList.add(Integer.parseInt(sc.next()));
        } {
            numList.add(Integer.parseInt(sc.next()));
        } numList.add(Integer.parseInt(sc.next())) numList.add numList Integer.parseInt(sc.next()) Integer.parseInt Integer sc.next() sc.next sc long count = numList.stream().distinct().count(); count numList.stream().distinct().count() numList.stream().distinct().count numList.stream().distinct() numList.stream().distinct numList.stream() numList.stream numList String str = N == count ? "YES" : "NO"; str N == count ? "YES" : "NO" N == count N count "YES" "NO" System.out.println(str) System.out.println System.out System System.out str String[] args args public class Main {
    public static void main(String[] args) throws Exception {
        Scanner sc = new Scanner(System.in);
        int N = Integer.parseInt(sc.next());
        List<Integer> numList = new ArrayList<>();
        for(int i=0;i<N;i++){
            numList.add(Integer.parseInt(sc.next()));
        }
        long count = numList.stream().distinct().count();
        String str = N == count ? "YES" : "NO";
        System.out.println(str);
}
} public class Main {
    public static void main(String[] args) throws Exception {
        Scanner sc = new Scanner(System.in);
        int N = Integer.parseInt(sc.next());
        List<Integer> numList = new ArrayList<>();
        for(int i=0;i<N;i++){
            numList.add(Integer.parseInt(sc.next()));
        }
        long count = numList.stream().distinct().count();
        String str = N == count ? "YES" : "NO";
        System.out.println(str);
}
} Main
import java.util.*;

public class Main {
    public static void main(String[] args) throws Exception {
        Scanner sc = new Scanner(System.in);
        int N = Integer.parseInt(sc.next());
        List<Integer> numList = new ArrayList<>();
        for(int i=0;i<N;i++){
            numList.add(Integer.parseInt(sc.next()));
        }
        long count = numList.stream().distinct().count();
        String str = N == count ? "YES" : "NO";
        System.out.println(str);
}
}