var
  n: integer;
begin
  readln(n);
  if (n>=1) and (n<=4) then
    writeln('few');
  if (n>=5) and (n<=9) then
    writeln('several');
  if (n>=10) and (n<=19) then
    writeln('pack');
  if (n>=20) and (n<=49) then
    writeln('lots');
  if (n>=50) and (n<=99) then
    writeln('horde');
  if (n>=100) and (n<=249) then
    writeln('throng');
  if (n>=250) and (n<=499) then
    writeln('swarm');
  if (n>=500) and (n<=999) then
    writeln('zounds');
  if n>=1000 then
    writeln('legion');
end.

will be better with CASE OF

IMHO, using CASE OF operator, You'll get more esthetic look, no more. And insignificant advantage in performance.

IlushaMax, could you check message year and don't answer if message is 2 (or more) years old?
Thanks in advance.