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