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

public class Main {

	public static void main(String[] args) {
		Scanner sc = new Scanner (System.in);
		int num = sc.nextInt();
		List<Integer> intArray = new ArrayList<>();

		for(int i=0 ; i<num ; i++) {
			intArray.add(sc.nextInt());
		}

		HashSet<Integer> type = new HashSet<>(intArray);

		System.out.print(type.size() < intArray.size() ? "NO" : "YES");
	}
} import java.util.ArrayList; ArrayList java.util import java.util.HashSet; HashSet java.util import java.util.List; List java.util import java.util.Scanner; Scanner java.util public class Main {

	public static void main(String[] args) {
		Scanner sc = new Scanner (System.in);
		int num = sc.nextInt();
		List<Integer> intArray = new ArrayList<>();

		for(int i=0 ; i<num ; i++) {
			intArray.add(sc.nextInt());
		}

		HashSet<Integer> type = new HashSet<>(intArray);

		System.out.print(type.size() < intArray.size() ? "NO" : "YES");
	}
} Main public static void main(String[] args) {
		Scanner sc = new Scanner (System.in);
		int num = sc.nextInt();
		List<Integer> intArray = new ArrayList<>();

		for(int i=0 ; i<num ; i++) {
			intArray.add(sc.nextInt());
		}

		HashSet<Integer> type = new HashSet<>(intArray);

		System.out.print(type.size() < intArray.size() ? "NO" : "YES");
	} main {
		Scanner sc = new Scanner (System.in);
		int num = sc.nextInt();
		List<Integer> intArray = new ArrayList<>();

		for(int i=0 ; i<num ; i++) {
			intArray.add(sc.nextInt());
		}

		HashSet<Integer> type = new HashSet<>(intArray);

		System.out.print(type.size() < intArray.size() ? "NO" : "YES");
	} Scanner sc = new Scanner (System.in); sc new Scanner (System.in) int num = sc.nextInt(); num sc.nextInt() sc.nextInt sc List<Integer> intArray = new ArrayList<>(); intArray new ArrayList<>() for(int i=0 ; i<num ; i++) {
			intArray.add(sc.nextInt());
		} int i=0 ; int i=0 ; i 0 i<num i num i++ i++ i {
			intArray.add(sc.nextInt());
		} {
			intArray.add(sc.nextInt());
		} intArray.add(sc.nextInt()) intArray.add intArray sc.nextInt() sc.nextInt sc HashSet<Integer> type = new HashSet<>(intArray); type new HashSet<>(intArray) System.out.print(type.size() < intArray.size() ? "NO" : "YES") System.out.print System.out System System.out type.size() < intArray.size() ? "NO" : "YES" type.size() < intArray.size() type.size() type.size type intArray.size() intArray.size intArray "NO" "YES" String[] args args public class Main {

	public static void main(String[] args) {
		Scanner sc = new Scanner (System.in);
		int num = sc.nextInt();
		List<Integer> intArray = new ArrayList<>();

		for(int i=0 ; i<num ; i++) {
			intArray.add(sc.nextInt());
		}

		HashSet<Integer> type = new HashSet<>(intArray);

		System.out.print(type.size() < intArray.size() ? "NO" : "YES");
	}
} public class Main {

	public static void main(String[] args) {
		Scanner sc = new Scanner (System.in);
		int num = sc.nextInt();
		List<Integer> intArray = new ArrayList<>();

		for(int i=0 ; i<num ; i++) {
			intArray.add(sc.nextInt());
		}

		HashSet<Integer> type = new HashSet<>(intArray);

		System.out.print(type.size() < intArray.size() ? "NO" : "YES");
	}
} Main
import java.util.ArrayList;
import java.util.HashSet;
import java.util.List;
import java.util.Scanner;

public class Main {

	public static void main(String[] args) {
		Scanner sc = new Scanner (System.in);
		int num = sc.nextInt();
		List<Integer> intArray = new ArrayList<>();

		for(int i=0 ; i<num ; i++) {
			intArray.add(sc.nextInt());
		}

		HashSet<Integer> type = new HashSet<>(intArray);

		System.out.print(type.size() < intArray.size() ? "NO" : "YES");
	}
}