Task: Program Execution
Input (English): Set1: '{4, 7, 10, 12, 13, 15, 16, 18, 19}', Set2: '{1, 3, 8, 9, 11, 12, 13, 15, 17, 18}'. How many elements are there in the intersection of Set1 and Set2 ?
Output (English): 4