A total of 110 students in the fifth grade of a certain school participated in three activity groups of Chinese, Mathematics, and English, and each person participated in at least one group. It is known that 52 people participated in the Chinese group, and 16 people only participated in the Chinese group; 61 people participated in the English group, and 15 people only participated in the English group; 21 people. So how many people participated in all three groups?
某学校五年级共有110人，参加语文、数学、英语三科活动小组，每人至少参加一组．已知参加语文小组的有52人，只参加语文小组的有16人；参加英语小组的有61人，只参加英语小组的有15人；参加数学小组的有63人，只参加数学小组的有21人．那么三组都参加的有多少人．
<gadget id="calculator">16 + 15 + 21</gadget>
<output>52</output>

<gadget id="calculator">110 - 52</gadget>
<output>58</output>

<gadget id="calculator">63 - 110 - 58</gadget>
<output>-105</output>

<gadget id="calculator">52 + 61 + (-105)</gadget>
<output>8</output>

<result>8</result>