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', 'A', '5913', 'L', '6615', '8013', 'L', '1117', '6193', 'B', 'T', 'X', '3569']

21, 1, 5913, 12, 6615, 8013, 12, 1117, 6193, 2, 20, 24, 3569