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: ['G', '3209', '4357', '3387', 'H', '8119', 's', 'u']

7, 3209, 4357, 3387, 8, 8119, 19, 21