Task: Program Execution
Input (English): 1, 4, 9, 4, t, 7
Output (English): [['1', '4', '9', '4', 't'], ['1', '4', '9', '4', '7'], ['1', '4', '9', 't', '7'], ['1', '4', '4', 't', '7'], ['1', '9', '4', 't', '7'], ['4', '9', '4', 't', '7']]