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: ['3389', '3183', 'u', 'B', 'H', 'l', '4713', '507', '159', '5839', '7911']

3389, 3183, 21, 2, 8, 12, 4713, 507, 159, 5839, 7911