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: ['4769', '529', '7187', '1453', '4137', '8029', 'q', '6799', 'e', '1275', 'm', '1243', '6171', 'G', '3011', 'l', 'M', '7831', 'B', 'U', '1803', '649', 'y', '9645', 'e', '7703', 'U', 'i', 'U', 'n']

4769, 529, 7187, 1453, 4137, 8029, 17, 6799, 5, 1275, 13, 1243, 6171, 7, 3011, 12, 13, 7831, 2, 21, 1803, 649, 25, 9645, 5, 7703, 21, 9, 21, 14