Task: Program Execution
Input (English): a, 1589, M, O, 7737, 6605, 1453, Q, 6877, 3439, M, 6887, U, 7587, i, 8651, U, 5355, S, T, 5213, f, H
Output (English): 1, 3, 4, 8, 11, 13, 15, 17, 19, 20, 22, 23