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 a []=new int [n];
        int b []=new int [n];
        for(int a0 = 0; a0 < n; a0++){
            int x = in.nextInt();
            a[a0]=x;
            int y = in.nextInt();
            b[a0]=y;
        }
        int p=0,q=0;
        for(int a0 = 1; a0 < n; a0++)
        {
            if(a[a0-1]==a[a0])
                p++;
             if(b[a0-1]==b[a0])
                q++;
            
        }
        if(p==n-1 || q==n-1)
            System.out.println("YES");
        else
             System.out.println("NO");
        
    }
}