Task: Program Execution
Input (English): Set1: '{2, 3, 6, 8, 11, 13, 15, 16, 20}', Set2: '{1, 2, 3, 4, 5, 7, 8, 17, 19, 20}'. How many elements are there in the intersection of Set1 and Set2 ?
Output (English): 4