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 xCoor[] = new int[n];
        int yCoor[] = new int[n];
        int prevX = -1;
        int prevY = -1;
        boolean isLine = true;

        for(int a0 = 0; a0 < n; a0++){
            int x = in.nextInt();
            int y = in.nextInt();            
            
            if(a0 == 0){
                prevX = x;
                prevY = y;
            }
            
            
            xCoor[a0] = x;
            yCoor[a0] = y;
        }
        
        for(int a1 = 0; a1 < n; a1++){
            if(prevX != xCoor[a1] && prevY !=yCoor[a1]){
                isLine = false;
                break;
            }
        }
        
        
        System.out.println( (isLine)?"YES":"NO");
        
    }
}