var n, count, factor;
begin
  ? n;
  if n < 0 then n := -n;
  count := 0;
  if n >= 2 then
  begin
    factor := 2;
    while factor <= n do
    begin
      while (n / factor) * factor = n do
      begin
        count := count + 1; n := n / factor
      end;
      factor := factor + 1
    end;
  end;
  if count = 2 then ! 1;
  if count <> 2 then ! 0
end.