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 x = 0, y = 0, n = in.nextInt();
        int prevX = in.nextInt(), prevY = in.nextInt();
        boolean sameX = true, sameY = true;
        
        for(int a0 = 0; a0 < n-1; a0++){
            x = in.nextInt();
            y = in.nextInt();
            
            if(sameX && x != prevX)
                sameX = false;
            if(sameY && y != prevY)
                sameY = false;
        }
        
        if(sameX || sameY)
            System.out.println("YES");
        else
            System.out.println("NO");
    }
}