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 arr[] = new int[n*2];
        for(int a0 = 0; a0 < n*2; a0++){
            int x = in.nextInt();
            
            arr[a0]=x;
        }
        boolean flag=false;
        boolean flag1=false;
        for(int j=0;j<=n*2-4;j+=2){
            if(arr[j]==arr[j+2]){
                flag=true;
            }
            else{
                flag=false;
                break;
            }
            
        }
         for(int j=1;j<=n*2-3;j+=2){
            if(arr[j]==arr[j+2]){
                flag1=true;
            }
            else{
                flag1=false;
                break;
            }
            
        }
        if(flag|| flag1){
            System.out.println("YES");
        }
        else{
            System.out.println("NO");
        }
    }
}