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: ['8863', '339', '5569', '6585', 'x', '2337', 'u']

8863, 339, 5569, 6585, 24, 2337, 21