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 scanner = new Scanner(System.in);
        int n = scanner.nextInt();
        boolean isXsame = true;
        boolean isYsame = true;
        
        int prevX = scanner.nextInt();
        int prevY = scanner.nextInt();
        boolean flag = true;
       
        for(int i = 1; i< n; i++){
            int x = scanner.nextInt();
            int y = scanner.nextInt();
            if(x != prevX){
            	isXsame = false;
            }
            if(y != prevY){
            	isYsame = false;
            }
        }
        
        System.out.println((isXsame || isYsame)==true?"YES":"NO");
    }
}