In a chorus of 28 people, everyone likes to drink one or more of black tea, green tea, scented tea, among them 9 people like to drink black tea, and 11 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28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9个人爱喝红茶，11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">28 - 9 - 11</gadget>
<output>8</output>

<result>8</result>