questionnaire survey was conducted on 100 people, and the result was that 28 people read magazine A; 30 people read magazine B; 42 people read magazine C; 8 people read magazines A and B at the same time; 10 people read magazines A and C at the same time; and C magazine; 3 people read these three magazines at the same time. How many people do not read any of the above three magazines?
针对100人做问卷调查，结果有28人阅读A杂志；30人读B杂志；42人读C杂志；8人同时阅读A与B杂志；10人同时阅读A与C杂志；5人同时阅读B与C杂志；有3人同时阅读这三种杂志．请问有多少人没有阅读上述三种杂志中的任何一种？
<gadget id="calculator">28 + 30 + 42</gadget>
<output>100</output>

<gadget id="calculator">5 - 3</gadget>
<output>2</output>

<gadget id="calculator">8 + 10 + 2</gadget>
<output>20</output>

<gadget id="calculator">100 - 20</gadget>
<output>80</output>

<gadget id="calculator">100 - 80</gadget>
<output>20</output>

<result>20</result>