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 isVerticale = true;
        boolean isHorizontal = true;
        int oldx = 0;
        int oldy = 0;
        for(int a0 = 0; a0 < n; a0++){
            int x = in.nextInt();
            int y = in.nextInt();
            if(oldx != x){
                isVerticale = false;
            }else{
                oldx = x;
            }
            if(oldy != y){
                isHorizontal = false;
            }else{
                oldy = y;
            }
        }
        
        if(isVerticale || isHorizontal){
            System.out.println("YES");
        }else{
            System.out.println("NO");
        }
    }
}