Task: Program Execution
Input (English): a, Z, 4, 5, u, b, 6
Output (English): [['a', 'Z', '4', '5', 'u', 'b'], ['a', 'Z', '4', '5', 'u', '6'], ['a', 'Z', '4', '5', 'b', '6'], ['a', 'Z', '4', 'u', 'b', '6'], ['a', 'Z', '5', 'u', 'b', '6'], ['a', '4', '5', 'u', 'b', '6'], ['Z', '4', '5', 'u', 'b', '6']]