Among those who participated in a certain activity, 47 could speak English, 38 could speak French, 22 could speak both, and the other 15 could only speak Chinese. How many people participated in the activity?
参加某项活动的人员中有47人会说英语，有38人会说法语，两种都会的有22人，另外15人只会讲汉语，一共有多少人参加了活动？
<gadget id="calculator">38 - 22</gadget>
<output>16</output>

<gadget id="calculator">47 + 16 + 15</gadget>
<output>78</output>

<result>78</result>