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: ['B', 'o', '3387', '5901', 'l', '9053', 'H', '1875']

2, 15, 3387, 5901, 12, 9053, 8, 1875