The Little Talents Training School selected a group of outstanding students to participate in the national composition competition and mathematics competition. As a result, 7 students won both competitions, and 13 students did not win both competitions. It is known that 12 students won prizes in the composition competition. There were 28 winners in the competition. So how many people are there in this batch of outstanding students?
小天才培训学校选出一批优秀的学生参加全国作文比赛和数学比赛，结果7人两项比赛都获奖了，有13人两项比赛都没有获奖，已知作文比赛获奖的有12人，数学比赛获奖的有28人．那么这批优秀的学生一共有多少人．
<gadget id="calculator">28 - 7</gadget>
<output>21</output>

<gadget id="calculator">12 + 21 + 13</gadget>
<output>46</output>

<result>46</result>