#include <iostream>
#include <string>
using namespace std;
struct node
           {
               char data;
               node* next;
           };
 class List
{ public:
 node* top,*marker,*prev,*tail;
 List();
        void Reset();
        void Move();
        bool EoList();
        void AddBeforeMarker(char x);
        void push_back (char x);
        void push_front (char x);
        void MarkerInTheEnd ();
        void Del();
		bool Empty();
};


class text : public List
{
public:
		List MyList;
		List Word;
		node * LocalTop;


    void createlist();
    void look();
    bool litter1(char x);
    bool litter2(char x);
    bool litter3(char x);
    bool word(char * x);
    bool poli();
    void povorot();
    void write();
    void del();
};

List::List()
{
  top=marker=tail=prev=NULL;

}
bool List::Empty () {
	return top==NULL;
}
void List::Reset()
{
    marker = top;
     prev=top;
}
void List::Move()
{
  marker=marker->next;
}
bool List::EoList()
{
    return marker==NULL;
}
void List::AddBeforeMarker(char x)
{
 node * t = new node;
 t->next=marker;
 t->data=x;
 if (marker!=top)
 prev->next=t;
 else
 top=prev=t;

}


void List::Del()
{ if (marker!=tail){
if (top==marker){
	top=top->next;
    delete marker;
    marker=top; prev=top;
}
else {

 prev->next=marker->next;
 delete marker;
 marker=marker->next;
}
}
else
{
	if (top==marker){
delete marker;
marker=NULL; prev=NULL;
}
else{
	prev->next=NULL;
	delete marker;
tail=marker=prev;
node * run = top;
while (run->next!=tail) run=run->next;
prev=run;
}
}
}
  void List::push_back (char x)
  {
  	if (top==NULL)
  	{ top=new node;
  		top->next=NULL;
  		top->data=x;
  		tail=top;
	}
	else
	{ node * t= new node;
	 t->next=NULL;
	 t->data=x;
		tail->next=t;
		tail=t;
	}
  }
        void List::push_front (char x) {

        	if (top==NULL)
  	{ top=new node;
  		top->next=NULL;
  		top->data=x;
  		tail=top;
	}
	else
	{ node *r=marker, *y=prev;
	    Reset();
	    AddBeforeMarker(x);
	    if (r!=top->next)
	    marker=r; y=prev;
	}
		}

	void	List::MarkerInTheEnd ()
{  node * t = top;
	marker=tail;
while (t->next!=marker) t=t->next;
prev=t;
	}


void text::createlist()
{
string str;
getline (cin,str);
int i=0;
while (str.size()>i)
{	MyList.push_back(str[i]);
	i++;}
		MyList.Reset();
}
void text::look(){

if (!Word.Empty())
{	if (MyList.EoList()) LocalTop=0;
 Word.Reset();
 while (!Word.Empty()) Word.Del();

}
LocalTop=MyList.marker;
while (!MyList.EoList() && MyList.marker->data != ' ')
	{
		Word.push_back ( MyList.marker->data);
		MyList.Move();
	}
	Word.Reset();
}

 bool text::litter1(char x)
 {return Word.top->data==x;
 }
  bool text::litter2(char x)
 {  return Word.tail->data==x;

 }
  bool text::litter3(char x)
 { Word.Reset();
 do {
	if ( Word.marker->data==x)
		return 1;
     	Word.Move();
 }
 while (!Word.EoList());
 return 0;
 }
 bool text::word(char * x)
 {Word.Reset();
 int i=0;
 do
 { if (x[i]!=Word.marker->data)
	 return 0;
	 i++;
	 Word.Move();

 }
	 while ( x[i] !=0 && !Word.EoList());
	 if (x[i] ==0 && !Word.EoList()) return 1;


 }

    bool text::poli(){
    	List Stack;
		Word.Reset();
		do
		{
			Stack.push_front(Word.marker->data)	;
			Word.Move();
		}
    	while (Word.marker!=NULL);
		Stack.Reset();
		Word.Reset();
		while ( Word.marker->data==Stack.marker->data && Word.marker!=NULL && Stack.marker!=NULL)
		{
			Word.Move();
			Stack.Move();
		}
	if (Word.marker==NULL && Stack.marker==NULL ) return true;
	else return false;


	}
	 void text::povorot()
	 {
        List Stack;
		Word.Reset();
		do
		{
			Stack.push_front(Word.marker->data);
			Word.Move();
		}
    	while (!Word.EoList());
    	Word.Reset();
    	Stack.Reset();
    	node * t=LocalTop;
			do
		{
		Word.marker->data= Stack.marker->data;
		t->data= Stack.marker->data;
		Word.Move();
		Stack.Move();
		t=t->next;
		}
    	while (!Word.EoList());

	  }

		void text::write()
	    {
	    MyList.Reset();

	    while (!MyList.EoList())

	    {
	    	cout<<MyList.marker->data;
	    	MyList.Move();
		}

		}
	 void text::del() {
	MyList.Reset();
	while (MyList.marker->next==LocalTop) MyList.Move();
node *	NewMark=MyList.marker;
	MyList.marker=LocalTop;
	while (!MyList.EoList() && MyList.marker->data!=' ')
	{MyList.Move();
	delete MyList.prev;
	}
	if (!MyList.EoList())
	{
		NewMark=MyList.marker->next;
		delete MyList.marker;
		MyList.marker=NewMark;
	}
	else
	 NewMark->next==NULL;
	 }

int main ()
{text NewText;
NewText.createlist();

}