import java.io.*;
import java.util.*;
import java.text.*;
import java.math.*;
import java.util.regex.*;

public class Solution {
 static Scanner std = new Scanner(System.in);
    	
    public static int nI(){
    	return std.nextInt();
    }

    public static long nL(){
    	return std.nextLong();
    }

    public static String next(){
    	return std.next();
    }

    public static String nextL(){
    	return std.nextLine();
    }
    
    public static int[] nA(int n){
        int[] arr = new int[n];
        for(int i=0;i<n;i++){
            arr[i] = nI();
        }
        return arr;
    }
    
    public static long fact(int n){
        if(n==1) return 1;
        return n*fact(n-1);
    }

    public static void printArray(int[] arr, int n ){
    	for(int i=0;i<n;i++) System.out.print(arr[i]+" ");
    	System.out.println();
    }

    public static void printArray2(int[][] arr, int n, int m){
    	for(int i=0;i<n;i++) for(int j=0;j<m;j++) System.out.print(arr[i][j]+" "); System.out.println();		
    }


    public static void print(String str){
        System.out.print(""+str+" ");
    }

    public static void pln(String str){
        System.out.println(""+str);
    }

    public static void main(String[] args) {
        /* Enter your code here. Read input from STDIN. Print output to STDOUT. Your class should be named Solution. */
        int n = nI();
        int[] arr = new int[n];
        int[] arr2 = new int[n];
        int c = 0;
        for(int h=0;h<n;h++){
             arr[h] = nI();
             arr2[h] = nI();
        }
        for(int h=1;h<n;h++){
            if(arr[h]!=arr[h-1]){
                c=1;
            }
        }
        if(c==0){
            pln("YES");
            return;
        }
        c=0;
        for(int h=1;h<n;h++){
            if(arr2[h]!=arr2[h-1]){
                c=1;
            }
        }
        if(c==0){
            pln("YES");
            return;
        } 
            pln("NO");
        

    }
}