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[] x = new int[n];
        int[] y = new int[n];
        for(int a0 = 0; a0 < n; a0++){
            x[a0] = in.nextInt();
            y[a0] = in.nextInt();
        }
        
        boolean isGood = true;
        for(int i = 0 ; i < n-1 ; i++){
            if(x[i] != x[i+1]){
                isGood = false;
                break;
            }
        }
        if(!isGood){
            int i;
            for(i = 0 ; i < n-1 ; i++){
                if(y[i] != y[i+1]){
                    isGood = false;
                    break;
                }
            }
            if(i == n-1){
                isGood = true;
            }
        }
        if(isGood)
            System.out.println("YES");
        else
            System.out.println("NO");
    }
}