Definition: In this task, you are given an input list A. You need to convert all the alphabets in the list with a number representing their position in the English alphabet. E.g., replace A by 1, B by 2, a by 1, b by 2, and so on.
Input: ['W', '1999', 'f', '4837', '1621', 'w', '4665', '9379', '5529', 'w', '1783', '6273', 'N', 'b', 'M', 'B', '7983', '5145', '4891', '2845', 'j', '8647', 'q', '7335', '7285', '6209']

23, 1999, 6, 4837, 1621, 23, 4665, 9379, 5529, 23, 1783, 6273, 14, 2, 13, 2, 7983, 5145, 4891, 2845, 10, 8647, 17, 7335, 7285, 6209