The page number of a book is composed of 3181 numbers, how many pages does the book have.
一本书的页码是由3181个数字组成，这本书共有多少页．
<gadget id="calculator">90 * 2</gadget>
<output>180</output>

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

<gadget id="calculator">9 + 180 + 2_700</gadget>
<output>2_889</output>

<gadget id="calculator">3_181 - 2_889</gadget>
<output>292</output>

<gadget id="calculator">292 / 4</gadget>
<output>73</output>

<gadget id="calculator">999 + 73</gadget>
<output>1_072</output>

<result>1_072</result>