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