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: ['R', 'c', 'C', '9953', '6485', '4943', '1725', '3007', '4125', '8717', 'U', 'd', '9323']

18, 3, 3, 9953, 6485, 4943, 1725, 3007, 4125, 8717, 21, 4, 9323