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=0 , b=0;
        boolean f1 = true , f2 = true;
        
        for(int a0 = 0; a0 < n; a0++){
            int x = in.nextInt();
            int y = in.nextInt();
            
            if( a0 == 0 )
                {
                a=x;
                b=y;
            }
            else
                {
                if(x!=a)
                    f1 = false;
                if(y!=b)
                    f2 = false;
            }
        }
        if(f1||f2)
            System.out.println("YES");
        else
            System.out.println("NO");
    }
}