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.

[EX Q]: Set1: '{2, 20, 4, 7}', Set2: '{2, 3, 7, 10, 13, 14, 15, 17, 20}'. How many elements are there in the intersection of Set1 and Set2 ?
[EX A]: 3

[EX Q]: Set1: '{16, 19, 20, 13}', Set2: '{2, 3, 4}'. How many elements are there in the intersection of Set1 and Set2 ?
[EX A]: 0

[EX Q]: Set1: '{1, 6, 11, 13, 16, 17, 18, 20}', Set2: '{17, 3, 9, 15}'. How many elements are there in the intersection of Set1 and Set2 ?
[EX A]:
1