primary school in Zhijin County organized students to participate in a sports meeting. There were 12 participants in the fourth grade, 7 less than the fifth grade, and the number of sixth grade participants was three times that of the fourth and fifth graders. How many people in the sixth grade participate in the sports meeting?
织金县某小学组织学生参加运动会，四年级有12人参加，比五年级少7人，六年级参加的人数是四、五年级参加的总人数的3倍．六年级有多少人参加运动会？
<gadget id="calculator">12 + 7 + 12</gadget>
<output>31</output>

<gadget id="calculator">31 * 3</gadget>
<output>93</output>

<result>93</result>