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.

Input: Consider Input: Set1: '{4, 6, 9, 12, 15, 17, 18}', Set2: '{4, 8, 11, 16, 20}'. How many elements are there in the intersection of Set1 and Set2 ?

Output: 1


Input: Consider Input: Set1: '{9, 3, 6, 7}', Set2: '{3, 4, 9, 10, 11, 15, 16, 17, 18}'. How many elements are there in the intersection of Set1 and Set2 ?

Output: 2


Input: Consider Input: Set1: '{3, 4, 7, 10, 13, 15, 17, 18, 19, 20}', Set2: '{12, 13, 6}'. How many elements are there in the intersection of Set1 and Set2 ?


Output: 1