Among the 12 people, there are 7 people who love singing, 6 people who love sports, 3 people who love both singing and sports, and how many people don't like singing and sports.
在12人中爱唱歌的有7人，爱体育的有6人，又爱唱歌又爱体育的有3人，不爱唱歌不爱体育的有多少人．
<gadget id="calculator">7 + 6</gadget>
<output>13</output>

<gadget id="calculator">13 - 3</gadget>
<output>10</output>

<gadget id="calculator">12 - 10</gadget>
<output>2</output>

<result>2</result>