> //Dec 12 2009
> #include<iostream>
> #include<string>
> using namespace std;
> int main()
> {
> 	string command,URL,fstack[101],bstack[101],curent_page;
> 	curent_page="http://www.acm.org/";
> 	int bp=-1,fp=-1;
> 	while(cin>>command)
> 	{
> 		if(command=="VISIT")
> 		{
> 			cin>>URL;
> 			bstack[++bp]=curent_page;
> 			curent_page=URL;
> 			fp=-1;
> 			cout<<curent_page<<endl;
> 		}
> 		else if(command=="BACK")
> 		{
> 			if(bp==-1)
> 				cout<<"Ignored"<<endl;
> 			else 
> 			{
> 				fstack[++fp]=curent_page;
> 				curent_page=bstack[bp--];
> 				cout<<curent_page<<endl;
> 			}
> 		}
> 		else if(command=="FORWARD")
> 		{
> 			if(fp==-1)
> 				cout<<"Ignored"<<endl;
> 			else
> 			{
> 				bstack[++bp]=curent_page;
> 				curent_page=fstack[fp--];
> 				cout<<curent_page<<endl;
> 			}
> 		}
> 		else  if(command=="QUIT")
> 			break;
> 	}
> 	return 0;
> }