It takes 3089 numbers to arrange the page number of a book. How many pages does this book have.
编排一本书的页码，共用了3089个数字，这本书有多少页．
<gadget id="calculator">2 * 90</gadget>
<output>180</output>

<gadget id="calculator">3 * 900</gadget>
<output>2_700</output>

<gadget id="calculator">3_089 - 9 - 180 - 2_700</gadget>
<output>200</output>

<gadget id="calculator">200 / 4</gadget>
<output>50</output>

<gadget id="calculator">50 - 1</gadget>
<output>49</output>

<gadget id="calculator">1_000 + 49</gadget>
<output>1_049</output>

<result>1_049</result>