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: ['5859', '3515', 'w', 'O', 'x', 'k', '3435', 'X', 'v', '2121', 'U', 'y', '2881', '8487', 'B', '7565', '6047', '1093', 'I', '8561', '4919', '6371', 'U', 'f', '8455', 'z', 'g', 'A', '4393', 'g', 'G', '4331', '6703', 'W', 'U', 'l', '5675', 'o']

5859, 3515, 23, 15, 24, 11, 3435, 24, 22, 2121, 21, 25, 2881, 8487, 2, 7565, 6047, 1093, 9, 8561, 4919, 6371, 21, 6, 8455, 26, 7, 1, 4393, 7, 7, 4331, 6703, 23, 21, 12, 5675, 15