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 flag1=true,flag2=true;
        int prevx=in.nextInt(),prevy=in.nextInt();
        for(int a0 = 1; a0 < n; a0++){
            int x = in.nextInt();
            int y = in.nextInt();
            if(prevx!=x){
                flag1&=false;
            }
            if(prevy!=y){
                flag2&=false;
            }
            prevx=x;
            prevy=y;
        }
        if(flag1||flag2){
            System.out.println("YES");
        }else{
            System.out.println("NO");
        }
    }
}