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

public class Solution {

    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        int n = in.nextInt();
        int arr1[]=new int[n];
        int arr2[]=new int[n];
        
        for(int a0 = 0; a0 < n; a0++){
            int x = in.nextInt();
            int y = in.nextInt();
            arr1[a0]=x;
            arr2[a0]=y;
        }
        int c=0,d=0;
        for(int i=1;i<n;i++){
            if(arr1[i]==arr1[i-1]) {
                c++;
               // System.out.println(arr1[i]+" "+arr1[i-1]);
            }
                else if(arr2[i]==arr2[i-1])
                    d++;
            }
        
        if(c==n-1 || d==n-1)
            System.out.println("YES");
        
        else  System.out.println("NO");
    }
}