Among the school interest groups, 36 people participated in the art group, 58 people participated in the football group, 29 people participated in the vocal music group, 16 people participated in the art group and football group at the same time, and 58 people participated in the football group and vocal music group at the same time. 12 people, 8 people participated in the art group and vocal music group at the same time, 4 people participated in all three activities at the same time, how many people participated in the interest group?
学校兴趣小组中，参加美术小组的有36人，参加足球小组的有58人，参加声乐小组的有29人，同时参加美术小组与足球小组的有16人，同时参加足球小组与声乐小组的有12人，同时参加美术小组与声乐小组的有8人，三种活动都同时参加的有4人，求参加兴趣小组的人数有多少？
<gadget id="calculator">36 - 16 - 8</gadget>
<output>12</output>

<gadget id="calculator">12 + 4</gadget>
<output>16</output>

<gadget id="calculator">58 - 16 - 12</gadget>
<output>30</output>

<gadget id="calculator">29 - 8 - 12</gadget>
<output>9</output>

<gadget id="calculator">16 + 30 + 4 + 9 + 4</gadget>
<output>63</output>

<gadget id="calculator">2 * 4</gadget>
<output>8</output>

<gadget id="calculator">8 - 8</gadget>
<output>0</output>

<gadget id="calculator">16 + 12 + 0</gadget>
<output>28</output>

<gadget id="calculator">63 + 28</gadget>
<output>91</output>

<result>91</result>