Task: Program Execution
Input (English): r, 7499, j, 9907, P, S, 2097, 8787, 489, O, Z, 1501, 6909, 4539, 2841, 2013, g, a, 4683, 3907, x, O
Output (English): 2, 4, 7, 8, 9, 12, 13, 14, 15, 16, 19, 20