Task: Program Execution
Input (English): y, 3487, Y, H, 2981, h, C, v, 2865, W, 993, 221, s, 2163, L, 4989, 4945, e, F, d, I
Output (English): 1, 3, 4, 6, 7, 8, 10, 13, 15, 18, 19, 20, 21