Task: Program Execution
Input (English): Set1: '{3, 5, 6, 8, 12, 14, 15, 17, 18, 20}', Set2: '{1, 5, 7, 8, 9, 10, 12, 15, 17, 20}'. How many elements are there in the union of Set1 and Set2 ?
Output (English): 14