Task: Program Execution
Input (English): 19, 20, ['x', '6239', 'D', 'l', 'Y', 'd', '6405', 'l', '2629', '4743', '8271', '3749', 'W', 'r', '9153', '2941', '6477', '2623', 'F', 'J']
Output (English): JF