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: ['6863', 'w', '8919', 'w', 'Y', 'K', 'C', '1801', 'h', 'g', 'Y', '8709', '3725', 'p', '1033', 'y', '8339', '7777', 'V', 'B', '4223', 'U']

6863, 23, 8919, 23, 25, 11, 3, 1801, 8, 7, 25, 8709, 3725, 16, 1033, 25, 8339, 7777, 22, 2, 4223, 21