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', 'W', '473', 'T', 'U', 'I', 'M', '4025', '8255', 'z', 'L', '8053', 'H', 'R', '3273', 'p', 'v', 'X', 's', 'O', 'q', '6273', 'M', 'V', '7775', '9025', '2529', 'U', 'a', 'K', 'H', '4521', '1287', 't', 'C', '2621']

21, 23, 473, 20, 21, 9, 13, 4025, 8255, 26, 12, 8053, 8, 18, 3273, 16, 22, 24, 19, 15, 17, 6273, 13, 22, 7775, 9025, 2529, 21, 1, 11, 8, 4521, 1287, 20, 3, 2621