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[] i = new int[n];
        int[] j = new int[n];
        
        for(int a0 = 0; a0 < n; a0++){
            int x = in.nextInt();
            int y = in.nextInt();
            i[a0] = x;
            j[a0] = y;
        }
        int s = i[0];
        int f1 = 0;
         for(int a0 = 0; a0 < n; a0++){
            if(i[a0] != s){
                f1=1;
                break;
            }
        }
        s = j[0];
        int f2 = 0;
         for(int a0 = 0; a0 < n; a0++){
            if(j[a0] != s){
                f2=1;
                break;
            }
        }
        if(f1==0 || f2==0)
            System.out.println("YES");
        else
            System.out.println("NO");
    }
}