procedure DeleteTrash(var S: String);

var
  Res: String;
  i: Integer;
  IsEmpty: Boolean;

begin
{  Res := '';
  S := Res + ' ';

  i := 1;
  while (i <= Length(S)) and ((i + 1) <= Length(S)) do
    begin
      if ((S[i] >= 'a') and (S[i] <= 'z')) or ((S[i] >= 'A') and (S[i] <= 'Z')) then
        Res := Res + S[i]
      else
        if ((S[i + 1] >= 'a') and (S[i + 1] <= 'z')) or ((S[i + 1] >= 'A') and (S[i + 1] <= 'Z')) then
          Res := Res + ' ';
      Inc(i);
    end;

  if (Res[1] = ' ') and (Length(Res) <> 1) then
    Delete(Res, 1, 1)
  else
    if (Res[1] = ' ') and (Length(Res) = 1) then
      S := '';

  if S[length(S)] <> ' ' then
    S := Res + ' ';
}

  Res := '';
  S := S + ' ';

  IsEmpty := True;
  for i := 1 to Length(S) do
    if ((S[i] >= 'a') and (S[i] <= 'z')) or ((S[i] >= 'A') and (S[i] <= 'Z')) then
      IsEmpty := False;

  if not IsEmpty then
    begin
      i := 1;
      while i <= Length(S) - 1 do
        begin
          if ((S[i] >= 'a') and (S[i] <= 'z')) or ((S[i] >= 'A') and (S[i] <= 'Z')) then
            Res := Res + S[i]
          else
            if ((S[i + 1] >= 'a') and (S[i + 1] <= 'z')) or ((S[i + 1] >= 'A') and (S[i + 1] <= 'Z')) then
              Res := Res + ' ';
          Inc(i);
        end;
      Res := Res + ' ';
    end
  else
    Res := '';

  S := Res;

end;