Part 1. Definition
In this task, you are given two sets, and you need to count the number of elements at the intersection of two given sets.  A Set is shown by two curly braces and comma-separated numbers inside, like {1, 2, 3}. The intersection of two given sets is the largest set which contains all the elements that are common to both sets. To find the intersection of two given sets, A and B is a set consisting of all the elements common to both A and B.
Part 2. Example
Set1: '{11, 4, 6}', Set2: '{2, 3, 4, 10, 11, 20}'. How many elements are there in the intersection of Set1 and Set2 ?
Answer: 2
Explanation: Intersection of Set1 and Set2 is {11, 4} and it has 2 elements. So, the answer is 2.
Part 3. Exercise
Set1: '{2, 10, 19, 14}', Set2: '{1, 4, 8, 9, 18}'. How many elements are there in the intersection of Set1 and Set2 ?
Answer:
0