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 arr[]=new int[(n*3)];
        int j=0;
        for(int a0 = 0; a0 < n; a0++){
            int x = in.nextInt();
            int y = in.nextInt();
            
            
            arr[j]=x;
            j++;
            arr[j]=y;
            j++;
        }
        String count="";
        for(int i=0;i<arr.length;i++){
            if(i%2==0){
                if(arr[i]==0){
                    count="YES";
                    
                }else if(arr[i]>=1){
                    count="NO";
                    break;
                }
               
            }
        }
        System.out.println(count);
    }
}