Task: Program Execution
Input (English): u, 6873, 3753, p, i, 1669, q, X, 4193, C, S, k, M, 5155, 5371, 2219, 4177, P, 6603, 1007, 8863
Output (English): 2, 3, 6, 9, 14, 15, 16, 17, 19, 20, 21