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: ['3187', 'D', '867', 'U', '29', 'm', '833', '3069']

3187, 4, 867, 21, 29, 13, 833, 3069