Task: Program Execution
Input (English): 9, x, 4, 5, 1, u, 2
Output (English): [['9', 'x', '4', '5', '1', 'u'], ['9', 'x', '4', '5', '1', '2'], ['9', 'x', '4', '5', 'u', '2'], ['9', 'x', '4', '1', 'u', '2'], ['9', 'x', '5', '1', 'u', '2'], ['9', '4', '5', '1', 'u', '2'], ['x', '4', '5', '1', 'u', '2']]