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