Each page of a book is marked with a page number, sharing 495 numbers (for example, page 36 uses two numbers 3 and 6). How many pages does this book have?
一本书的各页上标着页码，共用了495个数字(如第36页用3、6两个数字)．这本书共有多少页？
<gadget id="calculator">2 * 90</gadget>
<output>180</output>

<gadget id="calculator">495 - 180 - 9</gadget>
<output>306</output>

<gadget id="calculator">306 / 3</gadget>
<output>102</output>

<gadget id="calculator">99 + 102</gadget>
<output>201</output>

<result>201</result>