import java.util.LinkedHashSet;
import java.util.Scanner;
import java.util.Set;

public class Main {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		//━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
		int n = sc.nextInt();
		int[] numbers = new int[n];
		for (int i=0;i<n;i++) {
			numbers[i] = sc.nextInt();
		}
		int numbers_length = numbers.length;
		Set<Integer> linkedHashSet = new LinkedHashSet<Integer>();
		for (int i = 0; i < numbers.length; i++) {
			linkedHashSet.add(numbers[i]);
		}
		int numbers_length2 =linkedHashSet.size();
		
	if(numbers_length==numbers_length2){
		System.out.println("YES");
	} else{
		System.out.println("NO");
	}
		
		//━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
	}
} import java.util.LinkedHashSet; LinkedHashSet java.util import java.util.Scanner; Scanner java.util import java.util.Set; Set java.util public class Main {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		//━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
		int n = sc.nextInt();
		int[] numbers = new int[n];
		for (int i=0;i<n;i++) {
			numbers[i] = sc.nextInt();
		}
		int numbers_length = numbers.length;
		Set<Integer> linkedHashSet = new LinkedHashSet<Integer>();
		for (int i = 0; i < numbers.length; i++) {
			linkedHashSet.add(numbers[i]);
		}
		int numbers_length2 =linkedHashSet.size();
		
	if(numbers_length==numbers_length2){
		System.out.println("YES");
	} else{
		System.out.println("NO");
	}
		
		//━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
	}
} Main public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		//━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
		int n = sc.nextInt();
		int[] numbers = new int[n];
		for (int i=0;i<n;i++) {
			numbers[i] = sc.nextInt();
		}
		int numbers_length = numbers.length;
		Set<Integer> linkedHashSet = new LinkedHashSet<Integer>();
		for (int i = 0; i < numbers.length; i++) {
			linkedHashSet.add(numbers[i]);
		}
		int numbers_length2 =linkedHashSet.size();
		
	if(numbers_length==numbers_length2){
		System.out.println("YES");
	} else{
		System.out.println("NO");
	}
		
		//━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
	} main {
		Scanner sc = new Scanner(System.in);
		//━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
		int n = sc.nextInt();
		int[] numbers = new int[n];
		for (int i=0;i<n;i++) {
			numbers[i] = sc.nextInt();
		}
		int numbers_length = numbers.length;
		Set<Integer> linkedHashSet = new LinkedHashSet<Integer>();
		for (int i = 0; i < numbers.length; i++) {
			linkedHashSet.add(numbers[i]);
		}
		int numbers_length2 =linkedHashSet.size();
		
	if(numbers_length==numbers_length2){
		System.out.println("YES");
	} else{
		System.out.println("NO");
	}
		
		//━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
	} Scanner sc = new Scanner(System.in); sc new Scanner(System.in) int n = sc.nextInt(); n sc.nextInt() sc.nextInt sc int[] numbers = new int[n]; numbers new int[n] n for (int i=0;i<n;i++) {
			numbers[i] = sc.nextInt();
		} int i=0; int i=0; i 0 i<n i n i++ i++ i {
			numbers[i] = sc.nextInt();
		} {
			numbers[i] = sc.nextInt();
		} numbers[i] = sc.nextInt() numbers[i] numbers i sc.nextInt() sc.nextInt sc int numbers_length = numbers.length; numbers_length numbers.length numbers numbers.length Set<Integer> linkedHashSet = new LinkedHashSet<Integer>(); linkedHashSet new LinkedHashSet<Integer>() for (int i = 0; i < numbers.length; i++) {
			linkedHashSet.add(numbers[i]);
		} int i = 0; int i = 0; i 0 i < numbers.length i numbers.length numbers numbers.length i++ i++ i {
			linkedHashSet.add(numbers[i]);
		} {
			linkedHashSet.add(numbers[i]);
		} linkedHashSet.add(numbers[i]) linkedHashSet.add linkedHashSet numbers[i] numbers i int numbers_length2 =linkedHashSet.size(); numbers_length2 linkedHashSet.size() linkedHashSet.size linkedHashSet if(numbers_length==numbers_length2){
		System.out.println("YES");
	} else{
		System.out.println("NO");
	} numbers_length==numbers_length2 numbers_length numbers_length2 {
		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 sc = new Scanner(System.in);
		//━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
		int n = sc.nextInt();
		int[] numbers = new int[n];
		for (int i=0;i<n;i++) {
			numbers[i] = sc.nextInt();
		}
		int numbers_length = numbers.length;
		Set<Integer> linkedHashSet = new LinkedHashSet<Integer>();
		for (int i = 0; i < numbers.length; i++) {
			linkedHashSet.add(numbers[i]);
		}
		int numbers_length2 =linkedHashSet.size();
		
	if(numbers_length==numbers_length2){
		System.out.println("YES");
	} else{
		System.out.println("NO");
	}
		
		//━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
	}
} public class Main {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		//━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
		int n = sc.nextInt();
		int[] numbers = new int[n];
		for (int i=0;i<n;i++) {
			numbers[i] = sc.nextInt();
		}
		int numbers_length = numbers.length;
		Set<Integer> linkedHashSet = new LinkedHashSet<Integer>();
		for (int i = 0; i < numbers.length; i++) {
			linkedHashSet.add(numbers[i]);
		}
		int numbers_length2 =linkedHashSet.size();
		
	if(numbers_length==numbers_length2){
		System.out.println("YES");
	} else{
		System.out.println("NO");
	}
		
		//━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
	}
} Main
import java.util.LinkedHashSet;
import java.util.Scanner;
import java.util.Set;

public class Main {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		//━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
		int n = sc.nextInt();
		int[] numbers = new int[n];
		for (int i=0;i<n;i++) {
			numbers[i] = sc.nextInt();
		}
		int numbers_length = numbers.length;
		Set<Integer> linkedHashSet = new LinkedHashSet<Integer>();
		for (int i = 0; i < numbers.length; i++) {
			linkedHashSet.add(numbers[i]);
		}
		int numbers_length2 =linkedHashSet.size();
		
	if(numbers_length==numbers_length2){
		System.out.println("YES");
	} else{
		System.out.println("NO");
	}
		
		//━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
	}
}