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) {
       
        
    
    int n;
    Scanner s=new Scanner(System.in);
    n=s.nextInt();
    int flag=0,flag1=0,output=0;
    for(int i=0;i<n;i++)
    {
        int x=s.nextInt();
        int y=s.nextInt();
        if(i==0)
        {
        if(x==0)
            flag=1;
        else
            flag1=1;
        }
        else
        {
          if(flag==1)
          {
              if(x!=0&&output==0)
                  output=1;
          }
          if(flag1==1)
          {
              if(y!=0&&output==0)
                  output=1;
          }
        }
    }
    if(output==0)
        System.out.println("YES");
    else
        System.out.println("NO");
}
}