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: ['d', '9857', '9257', 'U', 'R', 'Y', '3931']

4, 9857, 9257, 21, 18, 25, 3931