They are preparing to participate in the gymnastics performance, and they stand in a square formation with 17 rows and 17 columns. Due to the reason of the venue, they need to add 3 rows and 3 columns. How many more people do they need?
准备参加体操表演，他们站成了一个17行17列的方阵，由于场地原因，需增加3行3列，求需要增加多少人？
<gadget id="calculator">17 + 3</gadget>
<output>20</output>

<gadget id="calculator">20 * 20</gadget>
<output>400</output>

<gadget id="calculator">17 * 17</gadget>
<output>289</output>

<gadget id="calculator">400 - 289</gadget>
<output>111</output>

<result>111</result>