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: ['4153', '4791', 'O', 't', '6081', '5087', '8157', 'k', 's', 'n', 'y', '4457', '1643', 'p']

4153, 4791, 15, 20, 6081, 5087, 8157, 11, 19, 14, 25, 4457, 1643, 16