program autogrill;
var Q,i,j,lung: Int64;
    t : char;
    grillaperti,p: string;
 
Procedure inizia;
begin
SetLength(grillaperti,0);
lung:=0;
end;
 
procedure apri(p :string);
begin
  Insert(p,grillaperti,lung);
  SetLength(grillaperti,lung+1);
  lung:=length(grillaperti);
  for j:=0 to lung do writeln(grillaperti[j]);   
end;
 
procedure chiudi (p:string);
begin
  Delete(grillaperti,lung-1,1);
  SetLength(grillaperti,lung-1);
  lung:=length(grillaperti);
  for j:=0 to lung do writeln(grillaperti[j]);   
end;
 
procedure chiedi(p:string);
 begin
 writeln('ciao');
 end;
 
begin
	readln(Q);
	for i:=0 to Q-1 do
	          begin
	            readln(t,p);
	            if t='a' then apri(p)
	                     else if t='c' then chiudi(p);
 
	          end;
 
end.
 

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NwpxIDMKYSA1CnEgNAphIDIKYyA1CmEgNgpxIDQ=

7
q 3
a 5
q 4
a 2
c 5
a 6
q 4