Task: Program Execution
Input (English): Set1: '{1, 2, 4, 6, 7, 9, 13, 17, 18, 19}', Set2: '{2, 4, 7, 8, 10, 11, 13, 16, 20}'. How many elements are there in the intersection of Set1 and Set2 ?
Output (English): 4