Task: Program Execution
Input (English): Q, 7577, U, 7987, D, t, 523, C, 2789, 8697, 4123, g, I, 573, 857, P, 969, 3677, 6665, y, D, 1559
Output (English): 1, 3, 5, 6, 8, 12, 13, 16, 20, 21