import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import java.util.stream.Collectors;

public class Main {

    public static void main(String[] args) throws Exception {

        InputStreamReader is = new InputStreamReader(System.in);
        BufferedReader reader = new BufferedReader(is);

        List<String> mylist = new ArrayList<>();

        // 標準入力からの値を変数strinputに代入
        String strinput = reader.readLine();

        while (strinput != null) {

            mylist.add(strinput);
            strinput = reader.readLine();

        }

        String arr01[] = mylist.get(0).split(" ");
        String arr02[] = mylist.get(1).split(" ");
        int n = Integer.valueOf(arr01[0]);

        List<String> list01 = Arrays.asList(arr02);
        List<String> list02 = list01.stream().distinct().collect(Collectors.toList());

        System.out.println(list01.size() == list02.size() ? "YES" : "NO");

    }

} import java.io.BufferedReader; BufferedReader java.io import java.io.InputStreamReader; InputStreamReader java.io import java.util.ArrayList; ArrayList java.util import java.util.Arrays; Arrays java.util import java.util.List; List java.util import java.util.stream.Collectors; Collectors java.util.stream public class Main {

    public static void main(String[] args) throws Exception {

        InputStreamReader is = new InputStreamReader(System.in);
        BufferedReader reader = new BufferedReader(is);

        List<String> mylist = new ArrayList<>();

        // 標準入力からの値を変数strinputに代入
        String strinput = reader.readLine();

        while (strinput != null) {

            mylist.add(strinput);
            strinput = reader.readLine();

        }

        String arr01[] = mylist.get(0).split(" ");
        String arr02[] = mylist.get(1).split(" ");
        int n = Integer.valueOf(arr01[0]);

        List<String> list01 = Arrays.asList(arr02);
        List<String> list02 = list01.stream().distinct().collect(Collectors.toList());

        System.out.println(list01.size() == list02.size() ? "YES" : "NO");

    }

} Main public static void main(String[] args) throws Exception {

        InputStreamReader is = new InputStreamReader(System.in);
        BufferedReader reader = new BufferedReader(is);

        List<String> mylist = new ArrayList<>();

        // 標準入力からの値を変数strinputに代入
        String strinput = reader.readLine();

        while (strinput != null) {

            mylist.add(strinput);
            strinput = reader.readLine();

        }

        String arr01[] = mylist.get(0).split(" ");
        String arr02[] = mylist.get(1).split(" ");
        int n = Integer.valueOf(arr01[0]);

        List<String> list01 = Arrays.asList(arr02);
        List<String> list02 = list01.stream().distinct().collect(Collectors.toList());

        System.out.println(list01.size() == list02.size() ? "YES" : "NO");

    } main {

        InputStreamReader is = new InputStreamReader(System.in);
        BufferedReader reader = new BufferedReader(is);

        List<String> mylist = new ArrayList<>();

        // 標準入力からの値を変数strinputに代入
        String strinput = reader.readLine();

        while (strinput != null) {

            mylist.add(strinput);
            strinput = reader.readLine();

        }

        String arr01[] = mylist.get(0).split(" ");
        String arr02[] = mylist.get(1).split(" ");
        int n = Integer.valueOf(arr01[0]);

        List<String> list01 = Arrays.asList(arr02);
        List<String> list02 = list01.stream().distinct().collect(Collectors.toList());

        System.out.println(list01.size() == list02.size() ? "YES" : "NO");

    } InputStreamReader is = new InputStreamReader(System.in); is new InputStreamReader(System.in) BufferedReader reader = new BufferedReader(is); reader new BufferedReader(is) List<String> mylist = new ArrayList<>(); mylist new ArrayList<>() String strinput = reader.readLine(); strinput reader.readLine() reader.readLine reader while (strinput != null) {

            mylist.add(strinput);
            strinput = reader.readLine();

        } strinput != null strinput null {

            mylist.add(strinput);
            strinput = reader.readLine();

        } mylist.add(strinput) mylist.add mylist strinput strinput = reader.readLine() strinput reader.readLine() reader.readLine reader String arr01[] = mylist.get(0).split(" "); arr01 mylist.get(0).split(" ") mylist.get(0).split mylist.get(0) mylist.get mylist 0 " " String arr02[] = mylist.get(1).split(" "); arr02 mylist.get(1).split(" ") mylist.get(1).split mylist.get(1) mylist.get mylist 1 " " int n = Integer.valueOf(arr01[0]); n Integer.valueOf(arr01[0]) Integer.valueOf Integer arr01[0] arr01 0 List<String> list01 = Arrays.asList(arr02); list01 Arrays.asList(arr02) Arrays.asList Arrays arr02 List<String> list02 = list01.stream().distinct().collect(Collectors.toList()); list02 list01.stream().distinct().collect(Collectors.toList()) list01.stream().distinct().collect list01.stream().distinct() list01.stream().distinct list01.stream() list01.stream list01 Collectors.toList() Collectors.toList Collectors System.out.println(list01.size() == list02.size() ? "YES" : "NO") System.out.println System.out System System.out list01.size() == list02.size() ? "YES" : "NO" list01.size() == list02.size() list01.size() list01.size list01 list02.size() list02.size list02 "YES" "NO" String[] args args public class Main {

    public static void main(String[] args) throws Exception {

        InputStreamReader is = new InputStreamReader(System.in);
        BufferedReader reader = new BufferedReader(is);

        List<String> mylist = new ArrayList<>();

        // 標準入力からの値を変数strinputに代入
        String strinput = reader.readLine();

        while (strinput != null) {

            mylist.add(strinput);
            strinput = reader.readLine();

        }

        String arr01[] = mylist.get(0).split(" ");
        String arr02[] = mylist.get(1).split(" ");
        int n = Integer.valueOf(arr01[0]);

        List<String> list01 = Arrays.asList(arr02);
        List<String> list02 = list01.stream().distinct().collect(Collectors.toList());

        System.out.println(list01.size() == list02.size() ? "YES" : "NO");

    }

} public class Main {

    public static void main(String[] args) throws Exception {

        InputStreamReader is = new InputStreamReader(System.in);
        BufferedReader reader = new BufferedReader(is);

        List<String> mylist = new ArrayList<>();

        // 標準入力からの値を変数strinputに代入
        String strinput = reader.readLine();

        while (strinput != null) {

            mylist.add(strinput);
            strinput = reader.readLine();

        }

        String arr01[] = mylist.get(0).split(" ");
        String arr02[] = mylist.get(1).split(" ");
        int n = Integer.valueOf(arr01[0]);

        List<String> list01 = Arrays.asList(arr02);
        List<String> list02 = list01.stream().distinct().collect(Collectors.toList());

        System.out.println(list01.size() == list02.size() ? "YES" : "NO");

    }

} Main
import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import java.util.stream.Collectors;

public class Main {

    public static void main(String[] args) throws Exception {

        InputStreamReader is = new InputStreamReader(System.in);
        BufferedReader reader = new BufferedReader(is);

        List<String> mylist = new ArrayList<>();

        // 標準入力からの値を変数strinputに代入
        String strinput = reader.readLine();

        while (strinput != null) {

            mylist.add(strinput);
            strinput = reader.readLine();

        }

        String arr01[] = mylist.get(0).split(" ");
        String arr02[] = mylist.get(1).split(" ");
        int n = Integer.valueOf(arr01[0]);

        List<String> list01 = Arrays.asList(arr02);
        List<String> list02 = list01.stream().distinct().collect(Collectors.toList());

        System.out.println(list01.size() == list02.size() ? "YES" : "NO");

    }

}
