const abc='abcdefghijklmnopqrstuvwxyz';
      did='ABCDEFGHIJKLMNOPQRSTUVWXYZ';

begin
zsk:=0;
i:=0;
assign(failas, 'prad.txt');
reset(failas);

/////////////////////////////////////////////////zodzius is bylos keliame i masyva
while not Eof(failas) do     //nuskaitom byla
begin
read(failas, r);
nr:=pos(r, did);          //keiciam didziasias raides i mazasias
if nr>0 then begin
keit:= copy(abc, nr, 1);
r:=keit[1];
end;


nr:=pos(r, abc);                  //atrenkam raides
if nr>0 then zodis1:=zodis1+r   //ir kuriam zodzius
        else begin
             if zodis1<>'' then begin
                zsk:=zsk+1;
                nr:=zsk;
                for i:=1 to nr do
                begin
                 if arr[i]=zodis1 then zsk:=zsk-1;
                 if (i=nr) and (zsk=nr) then begin
                 arr[i]:=zodis1;
                 zodis1:='';
                 end;
                end;
             end;
        zodis1:='';
        end;
end;

if zodis1<>'' then begin //dar karta patikriname, kad nuskaitytu paskutini simboli
 zsk:=zsk+1;
 nr:=zsk;
 for i:=1 to nr do
 begin
  if arr[i]=zodis1 then zsk:=zsk-1;
  if (i=nr) and (zsk=nr) then arr[i]:=zodis1;
 end;
end;

close(failas);