Task: Program Execution
Input (English): P, K, k, 7, 6, B, 9
Output (English): [['P', 'K', 'k', '7', '6', 'B'], ['P', 'K', 'k', '7', '6', '9'], ['P', 'K', 'k', '7', 'B', '9'], ['P', 'K', 'k', '6', 'B', '9'], ['P', 'K', '7', '6', 'B', '9'], ['P', 'k', '7', '6', 'B', '9'], ['K', 'k', '7', '6', 'B', '9']]