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(),tempx=0,tempy=0,xcount=1,ycount=1;
        
      for(int a0 = 0; a0 < n; a0++){
            int x = in.nextInt();
            int y = in.nextInt();
           if(a0!=0 && tempx==x)
          xcount++;
               if(a0!=0&& tempy==y)
                   ycount++;
               tempx=x;tempy=y;
           }
          if(xcount==n || ycount==n)
              System.out.println("YES");
          else
              System.out.println("NO");
           }
           
}