#include<bits/stdc++.h>
using namespace std;
int main(){
       int t;
       cin>>t;
       int i,j,k;
       int a[t][2];
       for(i=0;i<t;i++){
       	  for(j=0;j<2;j++){
       	  	cin>>a[i][j];
       	  }
       }
        int count=0,cnt=0;
        
        for(i=0;i<t;i++){
       	   
       	   	if(a[i][0]==0){
       	   		count+=1;
       	   	}
       	   		if(a[i][1]==0){
       	   		cnt++;
       	   	}
       	   
       	   
       	  
       }
      
       if(count==t){
       	cout<<"YES"<<endl;
       }
       else if(cnt==t)
       {
      	cout<<"YES"<<endl;
       }
       else{
       	cout<<"NO"<<endl;
       }
       
       return 0;
       
}