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