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', '9107', '351', 'a', '8693', 'O', 'I', '3675', '3883', '2709', '3999', '8265', '7627', '7041', '7799', 'U']

7, 9107, 351, 1, 8693, 15, 9, 3675, 3883, 2709, 3999, 8265, 7627, 7041, 7799, 21