/*package whatever //do not write package name here */

// Working program with FastReader 
import java.io.BufferedReader; 
import java.io.IOException; 
import java.io.InputStreamReader; 
import java.util.Scanner; 
import java.util.StringTokenizer; 
import java.util.*;
public class Main 
{ 
	static class FastReader 
	{ 
		BufferedReader br; 
		StringTokenizer st; 

		public FastReader() 
		{ 
			br = new BufferedReader(new
					InputStreamReader(System.in)); 
		} 

		String next() 
		{ 
			while (st == null || !st.hasMoreElements()) 
			{ 
				try
				{ 
					st = new StringTokenizer(br.readLine()); 
				} 
				catch (IOException e) 
				{ 
					e.printStackTrace(); 
				} 
			} 
			return st.nextToken(); 
		} 

		int nextInt() 
		{ 
			return Integer.parseInt(next()); 
		} 

		long nextLong() 
		{ 
			return Long.parseLong(next()); 
		} 

		double nextDouble() 
		{ 
			return Double.parseDouble(next()); 
		} 

		String nextLine() 
		{ 
			String str = ""; 
			try
			{ 
				str = br.readLine(); 
			} 
			catch (IOException e) 
			{ 
				e.printStackTrace(); 
			} 
			return str; 
		} 
	} 

	public static void main(String[] args) 
	{ 
		FastReader ob=new FastReader(); 
		int n = ob.nextInt();
		HashMap<Long,Long> map = new HashMap<Long,Long>();
		boolean flag=true;
		for (int i=0;i<n ;i++) {
		    long k = ob.nextLong();
		    if(map.containsKey(k)){
		        flag=false;
		    }
		    else{
		        map.put(k,(long)0);
		    }
		}
		if(flag){
		    System.out.println("YES");
		}
		else{
		    System.out.println("NO");
		}
	
	
	} 
}  import java.io.BufferedReader; BufferedReader java.io import java.io.IOException; IOException java.io import java.io.InputStreamReader; InputStreamReader java.io import java.util.Scanner; Scanner java.util import java.util.StringTokenizer; StringTokenizer java.util import java.util.*; util.* java public class Main 
{ 
	static class FastReader 
	{ 
		BufferedReader br; 
		StringTokenizer st; 

		public FastReader() 
		{ 
			br = new BufferedReader(new
					InputStreamReader(System.in)); 
		} 

		String next() 
		{ 
			while (st == null || !st.hasMoreElements()) 
			{ 
				try
				{ 
					st = new StringTokenizer(br.readLine()); 
				} 
				catch (IOException e) 
				{ 
					e.printStackTrace(); 
				} 
			} 
			return st.nextToken(); 
		} 

		int nextInt() 
		{ 
			return Integer.parseInt(next()); 
		} 

		long nextLong() 
		{ 
			return Long.parseLong(next()); 
		} 

		double nextDouble() 
		{ 
			return Double.parseDouble(next()); 
		} 

		String nextLine() 
		{ 
			String str = ""; 
			try
			{ 
				str = br.readLine(); 
			} 
			catch (IOException e) 
			{ 
				e.printStackTrace(); 
			} 
			return str; 
		} 
	} 

	public static void main(String[] args) 
	{ 
		FastReader ob=new FastReader(); 
		int n = ob.nextInt();
		HashMap<Long,Long> map = new HashMap<Long,Long>();
		boolean flag=true;
		for (int i=0;i<n ;i++) {
		    long k = ob.nextLong();
		    if(map.containsKey(k)){
		        flag=false;
		    }
		    else{
		        map.put(k,(long)0);
		    }
		}
		if(flag){
		    System.out.println("YES");
		}
		else{
		    System.out.println("NO");
		}
	
	
	} 
} Main public static void main(String[] args) 
	{ 
		FastReader ob=new FastReader(); 
		int n = ob.nextInt();
		HashMap<Long,Long> map = new HashMap<Long,Long>();
		boolean flag=true;
		for (int i=0;i<n ;i++) {
		    long k = ob.nextLong();
		    if(map.containsKey(k)){
		        flag=false;
		    }
		    else{
		        map.put(k,(long)0);
		    }
		}
		if(flag){
		    System.out.println("YES");
		}
		else{
		    System.out.println("NO");
		}
	
	
	} main { 
		FastReader ob=new FastReader(); 
		int n = ob.nextInt();
		HashMap<Long,Long> map = new HashMap<Long,Long>();
		boolean flag=true;
		for (int i=0;i<n ;i++) {
		    long k = ob.nextLong();
		    if(map.containsKey(k)){
		        flag=false;
		    }
		    else{
		        map.put(k,(long)0);
		    }
		}
		if(flag){
		    System.out.println("YES");
		}
		else{
		    System.out.println("NO");
		}
	
	
	} FastReader ob=new FastReader(); ob new FastReader() int n = ob.nextInt(); n ob.nextInt() ob.nextInt ob HashMap<Long,Long> map = new HashMap<Long,Long>(); map new HashMap<Long,Long>() boolean flag=true; flag true for (int i=0;i<n ;i++) {
		    long k = ob.nextLong();
		    if(map.containsKey(k)){
		        flag=false;
		    }
		    else{
		        map.put(k,(long)0);
		    }
		} int i=0; int i=0; i 0 i<n i n i++ i++ i {
		    long k = ob.nextLong();
		    if(map.containsKey(k)){
		        flag=false;
		    }
		    else{
		        map.put(k,(long)0);
		    }
		} {
		    long k = ob.nextLong();
		    if(map.containsKey(k)){
		        flag=false;
		    }
		    else{
		        map.put(k,(long)0);
		    }
		} long k = ob.nextLong(); k ob.nextLong() ob.nextLong ob if(map.containsKey(k)){
		        flag=false;
		    }
		    else{
		        map.put(k,(long)0);
		    } map.containsKey(k) map.containsKey map k {
		        flag=false;
		    } flag=false flag false {
		        map.put(k,(long)0);
		    } map.put(k,(long)0) map.put map k (long)0 if(flag){
		    System.out.println("YES");
		}
		else{
		    System.out.println("NO");
		} flag {
		    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 static class FastReader 
	{ 
		BufferedReader br; 
		StringTokenizer st; 

		public FastReader() 
		{ 
			br = new BufferedReader(new
					InputStreamReader(System.in)); 
		} 

		String next() 
		{ 
			while (st == null || !st.hasMoreElements()) 
			{ 
				try
				{ 
					st = new StringTokenizer(br.readLine()); 
				} 
				catch (IOException e) 
				{ 
					e.printStackTrace(); 
				} 
			} 
			return st.nextToken(); 
		} 

		int nextInt() 
		{ 
			return Integer.parseInt(next()); 
		} 

		long nextLong() 
		{ 
			return Long.parseLong(next()); 
		} 

		double nextDouble() 
		{ 
			return Double.parseDouble(next()); 
		} 

		String nextLine() 
		{ 
			String str = ""; 
			try
			{ 
				str = br.readLine(); 
			} 
			catch (IOException e) 
			{ 
				e.printStackTrace(); 
			} 
			return str; 
		} 
	} FastReader BufferedReader br; br StringTokenizer st; st public FastReader() 
		{ 
			br = new BufferedReader(new
					InputStreamReader(System.in)); 
		} FastReader { 
			br = new BufferedReader(new
					InputStreamReader(System.in)); 
		} br = new BufferedReader(new
					InputStreamReader(System.in)) br new BufferedReader(new
					InputStreamReader(System.in)) String next() 
		{ 
			while (st == null || !st.hasMoreElements()) 
			{ 
				try
				{ 
					st = new StringTokenizer(br.readLine()); 
				} 
				catch (IOException e) 
				{ 
					e.printStackTrace(); 
				} 
			} 
			return st.nextToken(); 
		} next { 
			while (st == null || !st.hasMoreElements()) 
			{ 
				try
				{ 
					st = new StringTokenizer(br.readLine()); 
				} 
				catch (IOException e) 
				{ 
					e.printStackTrace(); 
				} 
			} 
			return st.nextToken(); 
		} while (st == null || !st.hasMoreElements()) 
			{ 
				try
				{ 
					st = new StringTokenizer(br.readLine()); 
				} 
				catch (IOException e) 
				{ 
					e.printStackTrace(); 
				} 
			} st == null || !st.hasMoreElements() st == null st null !st.hasMoreElements() st.hasMoreElements() st.hasMoreElements st { 
				try
				{ 
					st = new StringTokenizer(br.readLine()); 
				} 
				catch (IOException e) 
				{ 
					e.printStackTrace(); 
				} 
			} try
				{ 
					st = new StringTokenizer(br.readLine()); 
				} 
				catch (IOException e) 
				{ 
					e.printStackTrace(); 
				} catch (IOException e) 
				{ 
					e.printStackTrace(); 
				} IOException e { 
					e.printStackTrace(); 
				} e.printStackTrace() e.printStackTrace e { 
					st = new StringTokenizer(br.readLine()); 
				} st = new StringTokenizer(br.readLine()) st new StringTokenizer(br.readLine()) return st.nextToken(); st.nextToken() st.nextToken st int nextInt() 
		{ 
			return Integer.parseInt(next()); 
		} nextInt { 
			return Integer.parseInt(next()); 
		} return Integer.parseInt(next()); Integer.parseInt(next()) Integer.parseInt Integer next() next long nextLong() 
		{ 
			return Long.parseLong(next()); 
		} nextLong { 
			return Long.parseLong(next()); 
		} return Long.parseLong(next()); Long.parseLong(next()) Long.parseLong Long next() next double nextDouble() 
		{ 
			return Double.parseDouble(next()); 
		} nextDouble { 
			return Double.parseDouble(next()); 
		} return Double.parseDouble(next()); Double.parseDouble(next()) Double.parseDouble Double next() next String nextLine() 
		{ 
			String str = ""; 
			try
			{ 
				str = br.readLine(); 
			} 
			catch (IOException e) 
			{ 
				e.printStackTrace(); 
			} 
			return str; 
		} nextLine { 
			String str = ""; 
			try
			{ 
				str = br.readLine(); 
			} 
			catch (IOException e) 
			{ 
				e.printStackTrace(); 
			} 
			return str; 
		} String str = ""; str "" try
			{ 
				str = br.readLine(); 
			} 
			catch (IOException e) 
			{ 
				e.printStackTrace(); 
			} catch (IOException e) 
			{ 
				e.printStackTrace(); 
			} IOException e { 
				e.printStackTrace(); 
			} e.printStackTrace() e.printStackTrace e { 
				str = br.readLine(); 
			} str = br.readLine() str br.readLine() br.readLine br return str; str public class Main 
{ 
	static class FastReader 
	{ 
		BufferedReader br; 
		StringTokenizer st; 

		public FastReader() 
		{ 
			br = new BufferedReader(new
					InputStreamReader(System.in)); 
		} 

		String next() 
		{ 
			while (st == null || !st.hasMoreElements()) 
			{ 
				try
				{ 
					st = new StringTokenizer(br.readLine()); 
				} 
				catch (IOException e) 
				{ 
					e.printStackTrace(); 
				} 
			} 
			return st.nextToken(); 
		} 

		int nextInt() 
		{ 
			return Integer.parseInt(next()); 
		} 

		long nextLong() 
		{ 
			return Long.parseLong(next()); 
		} 

		double nextDouble() 
		{ 
			return Double.parseDouble(next()); 
		} 

		String nextLine() 
		{ 
			String str = ""; 
			try
			{ 
				str = br.readLine(); 
			} 
			catch (IOException e) 
			{ 
				e.printStackTrace(); 
			} 
			return str; 
		} 
	} 

	public static void main(String[] args) 
	{ 
		FastReader ob=new FastReader(); 
		int n = ob.nextInt();
		HashMap<Long,Long> map = new HashMap<Long,Long>();
		boolean flag=true;
		for (int i=0;i<n ;i++) {
		    long k = ob.nextLong();
		    if(map.containsKey(k)){
		        flag=false;
		    }
		    else{
		        map.put(k,(long)0);
		    }
		}
		if(flag){
		    System.out.println("YES");
		}
		else{
		    System.out.println("NO");
		}
	
	
	} 
} public class Main 
{ 
	static class FastReader 
	{ 
		BufferedReader br; 
		StringTokenizer st; 

		public FastReader() 
		{ 
			br = new BufferedReader(new
					InputStreamReader(System.in)); 
		} 

		String next() 
		{ 
			while (st == null || !st.hasMoreElements()) 
			{ 
				try
				{ 
					st = new StringTokenizer(br.readLine()); 
				} 
				catch (IOException e) 
				{ 
					e.printStackTrace(); 
				} 
			} 
			return st.nextToken(); 
		} 

		int nextInt() 
		{ 
			return Integer.parseInt(next()); 
		} 

		long nextLong() 
		{ 
			return Long.parseLong(next()); 
		} 

		double nextDouble() 
		{ 
			return Double.parseDouble(next()); 
		} 

		String nextLine() 
		{ 
			String str = ""; 
			try
			{ 
				str = br.readLine(); 
			} 
			catch (IOException e) 
			{ 
				e.printStackTrace(); 
			} 
			return str; 
		} 
	} 

	public static void main(String[] args) 
	{ 
		FastReader ob=new FastReader(); 
		int n = ob.nextInt();
		HashMap<Long,Long> map = new HashMap<Long,Long>();
		boolean flag=true;
		for (int i=0;i<n ;i++) {
		    long k = ob.nextLong();
		    if(map.containsKey(k)){
		        flag=false;
		    }
		    else{
		        map.put(k,(long)0);
		    }
		}
		if(flag){
		    System.out.println("YES");
		}
		else{
		    System.out.println("NO");
		}
	
	
	} 
} Main
/*package whatever //do not write package name here */

// Working program with FastReader 
import java.io.BufferedReader; 
import java.io.IOException; 
import java.io.InputStreamReader; 
import java.util.Scanner; 
import java.util.StringTokenizer; 
import java.util.*;
public class Main 
{ 
	static class FastReader 
	{ 
		BufferedReader br; 
		StringTokenizer st; 

		public FastReader() 
		{ 
			br = new BufferedReader(new
					InputStreamReader(System.in)); 
		} 

		String next() 
		{ 
			while (st == null || !st.hasMoreElements()) 
			{ 
				try
				{ 
					st = new StringTokenizer(br.readLine()); 
				} 
				catch (IOException e) 
				{ 
					e.printStackTrace(); 
				} 
			} 
			return st.nextToken(); 
		} 

		int nextInt() 
		{ 
			return Integer.parseInt(next()); 
		} 

		long nextLong() 
		{ 
			return Long.parseLong(next()); 
		} 

		double nextDouble() 
		{ 
			return Double.parseDouble(next()); 
		} 

		String nextLine() 
		{ 
			String str = ""; 
			try
			{ 
				str = br.readLine(); 
			} 
			catch (IOException e) 
			{ 
				e.printStackTrace(); 
			} 
			return str; 
		} 
	} 

	public static void main(String[] args) 
	{ 
		FastReader ob=new FastReader(); 
		int n = ob.nextInt();
		HashMap<Long,Long> map = new HashMap<Long,Long>();
		boolean flag=true;
		for (int i=0;i<n ;i++) {
		    long k = ob.nextLong();
		    if(map.containsKey(k)){
		        flag=false;
		    }
		    else{
		        map.put(k,(long)0);
		    }
		}
		if(flag){
		    System.out.println("YES");
		}
		else{
		    System.out.println("NO");
		}
	
	
	} 
} 
