Task: Program Execution
Input (English): Set1: '{8, 9, 10, 11, 12, 13, 16, 19, 20}', Set2: '{3, 4, 7, 8, 9, 12, 14, 15, 18, 19}'. How many elements are there in the intersection of Set1 and Set2 ?
Output (English): 4