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: ['5407', 'B', '3531', '6199', '5409', '3339', 'F']

5407, 2, 3531, 6199, 5409, 3339, 6