Task: Program Execution
Input (English): 503 8877 s a 4097 777 d 4183 J 5345 249 6679 u a 1967 Z x 3201 P K 3517 O r 6031 g 4161 d S 669 1201
Output (English): 3, 4, 7, 9, 13, 14, 16, 17, 19, 20, 22, 23, 25, 27, 28