Task: Program Execution
Input (English): 2, 5, N, X, 7, X, 9
Output (English): [['2', '5', 'N', 'X', '7', 'X'], ['2', '5', 'N', 'X', '7', '9'], ['2', '5', 'N', 'X', 'X', '9'], ['2', '5', 'N', '7', 'X', '9'], ['2', '5', 'X', '7', 'X', '9'], ['2', 'N', 'X', '7', 'X', '9'], ['5', 'N', 'X', '7', 'X', '9']]