Task: Program Execution
Input (English): Set1: '{2, 3, 4, 6, 7, 8, 14, 15, 16, 17}', Set2: '{1, 6, 7, 8, 9, 11, 15, 18, 20}'. How many elements are there in the intersection of Set1 and Set2 ?
Output (English): 4