In a chorus of 30 people, everyone likes to drink one or more of black tea, green tea, scented tea, among them 10 people like to drink black tea, and 12 people don’t like to drink black tea but like to drink green tea. May I ask: How many people only love to drink scented tea?
在一个由30人组成的合唱队中，每个人都爱喝红茶、绿茶、花茶中的一种或者几种，其中有10个人爱喝红茶，12个人不爱喝红茶却爱喝绿茶，请问：只爱喝花茶的有多少人？
<gadget id="calculator">30 - 10 - 12</gadget>
<output>8</output>

<result>8</result>