A certain class planted trees on Arbor Day, divided into 3 groups, the first group each planted 5 trees, the second group each planted 4 trees, and the third group each planted 3 trees. It is known that the number of people in the second group is one-third of the sum of the number of the first and third groups, and the number of trees planted is 72 less than the sum of the numbers of the first and third groups. What is the minimum number of people in the class?
某班植树节植树，分为3个组，第一组每人植树5棵，第二组每人植树4棵，第三组每人植树3棵．已知第二组人数是第一、三两组人数之和的三分之一，植树棵数比第一、三两组棵数之和少72棵，则该班级至少有多少人．
<gadget id="calculator">4 * 8</gadget>
<output>32</output>

<result>32</result>