var
  s:string;
  m:set of char;
  i:integer;
begin
  writeln('Enter text...');
  readln(s);
  i:=1;
  repeat
    if s[i] in m then
      delete(s,i,1)
    else
    begin
      include(m,s[i]);
      inc(i)
    end
  until
    i>length(s);
  writeln('Result:');
  writeln(s);
  readln
end.