program targ;
type sent=string;
var
  str:sent;
procedure check(var s:sent);
var
   word,prev_word:sent_type;
   i,j:integer;
begin {procedure}
      i:=1;
      prev_word:='';
      while i<= length(s) do
            begin
                 word:='';
                 j:=i;
                 while (i<=length(s)) and (copy(s,i,1)<>'') do
                       begin
                            word:=word+copy(s,i,1);
                            i:=i+1;
                       end;
                 if word=prev_word then
                 begin
                    delete(s,j,length(word));
                 end;
                 prev_word:=word;
                 i:=i+1;
            end;
            writeln(s);
end;
begin
     writeln('enter string');
     readln(str);
     check(str);
end.
 מראש!!