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 x=in.nextInt();
        int y=in.nextInt();
        int r=x,c=y;
        boolean rf=true,cf=true;
        for(int a0 = 1; a0 < n; a0++){
             x = in.nextInt();
             y = in.nextInt();
            
            if(r!=x)
               rf=false;
            if(c!=y)
                cf=false;
        }
        if(rf || cf)
            System.out.println("YES");
        else
            System.out.println("NO");
    }
}