326 students from the fourth grade of the Experimental Primary School went to the Children's Paradise for activities. Among them, 182 took the pirate ship, 136 took the bumper car, and 158 played aerial shooting. There were 86 people who took the pirate ship and bumper car, 78 people who took the pirate ship and aerial shooting, and 42 people who took the bumper car and aerial shooting. How many people participated in all three activities?
实验小学四年级的326名学生到儿童乐园活动，其中乘海盗船的有182人，坐碰碰车的有136人，玩空中射击的有158人．既乘海盗船又坐碰碰车的有86人，既乘海盗船又玩空中射击的有78人，既坐碰碰车又玩空中射击的有42人，三种活动都参加的有多少人？
<gadget id="calculator">158 - 86 - 78 - 42</gadget>
<output>-48</output>

<gadget id="calculator">182 + 136 + (-48)</gadget>
<output>270</output>

<gadget id="calculator">326 - 270</gadget>
<output>56</output>

<result>56</result>