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: ['u', 'q', '3907', 'F', '9451', 'O', 'I', '5299']

21, 17, 3907, 6, 9451, 15, 9, 5299