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[] xs = new int[n];
        int[] ys = new int[n];
        
        for(int a0 = 0; a0 < n; a0++){
            in.nextLine();
            xs[a0] = in.nextInt();
            ys[a0] = in.nextInt();
        }
        
        System.out.println(process(xs, ys, n));
    }
    
    private static String process(int[] xs, int[] ys, int n) {
        int f;
        boolean found = true;
        
        f = xs[0];
        for(int i = 1; i < n; i++) {
            if(xs[i] != f) {
                found = false;
                break;
            }
        }
        
        if(found) {
            return "YES";
        }
        
        f = ys[0];
        for(int i = 1; i < n; i++) {
            if(ys[i] != f) {
                return "NO";
            }
        }
        
        return "YES";
        
    } 
}