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 k1=0,k2=0;
        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;
            
        }
        for(int i=1;i<n;i++)
            {
            if(arr1[i]==arr1[i-1])
                k1++;
            if(arr2[i]==arr2[i-1])
                k2++;
        }
       // System.out.println(k1+" "+k2);
        if(k1+1==n && k2+1==n)
            System.out.println("NO");
        else if(k1+1==n)
            System.out.println("YES");
            else if(k2+1==n)
            System.out.println("YES");
            else System.out.println("NO");
    }
}