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 c=0,d=0,e=0;
        for(int a0 = 0; a0 < n; a0++){
            
            int x = in.nextInt();
            int y = in.nextInt();
            if(y==0){
                c=c+1;
            }
            else if(x==0){
                d=d+1;
            }
        else {
            e=e+1;
        }
      
        }
        if(c==n){
       System.out.println("YES");
          
      }
       else if(d==n){
                  System.out.println("YES");

       }
        else{
                   System.out.println("NO");

        }
    }
}