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();
        boolean flag=true;
        int x1[]= new int[n];
        int y1[]= new int[n];
        int i=0;
        String s="";
        for(int a0 = 0; a0 < n; a0++){
            int x = in.nextInt();
            int y = in.nextInt();
            x1[i] = x;
            y1[i] = y;
            i++;
        }
        for(int j=0; j<n-1; j++){
            if(x1[j]!=x1[j+1] && y1[j]!=y1[j+1] ){
                s="NO";
                break;
            }
            else s="YES";
        }
        System.out.println(s);
    }
}