A comic book has 100 pages in total, and when arranging page numbers, one typeface can only arrange one number. Please calculate, how many typefaces are needed to arrange the page numbers of this book?
一本连环画共100页，排页码时一个铅字只能排一位数字．请你算一下，排这本书的页码共要用多少个铅字？
<gadget id="calculator">1 * 9</gadget>
<output>9</output>

<gadget id="calculator">2 * 90</gadget>
<output>180</output>

<gadget id="calculator">9 + 180 + 3</gadget>
<output>192</output>

<result>192</result>