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 fX = 0, fY = 0;
        boolean isV = true;
        boolean isH = true;
        
        for(int a0 = 0; a0 < n; a0++){
            
            if (a0 == 0) {
                fX = in.nextInt();
                fY = in.nextInt();
            } else {
                int x = in.nextInt();   
                int y = in.nextInt();
                if (x != fX)
                    isV = false;
                if (y != fY)
                    isH = false;
                if (!isV && !isH) {
                    System.out.println("NO");
                    break;
                }
            }
        }
        
        if (isV || isH)
            System.out.println("YES");
    }
}