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 notHor = 0, notVer = 0;
        int x[] = new int[n];
        int y[] = new int[n];
        for(int a0 = 0; a0 < n; a0++){
            x[a0] = in.nextInt();
            y[a0] = in.nextInt();
        }
        
        for(int i = 1; i < n; i++){
            if(x[i] != x[i-1]){
                notHor++;
            }
            if(y[i] != y[i-1]){
                notVer++;
            }
        }
        if(notHor == 0 || notVer == 0){
            System.out.println("YES");
        }
        else{
            System.out.println("NO");
        }
    }
}