Everyone in class 3 and 1 participates in at least one of the running and rope skipping competitions. It is known that there are 36 people who participated in the race, 38 people who participated in the rope skipping, and 19 people who participated in both. How many students are there in Class 1?
三1班每人至少参加赛跑和跳绳比赛中的一项．已知参加赛跑的有36人，参加跳绳的有38人，两项都参加的有19人，三1班有学生多少人？
<gadget id="calculator">38 - 19</gadget>
<output>19</output>

<gadget id="calculator">36 + 19</gadget>
<output>55</output>

<result>55</result>