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: ['A', 'D', '8911', '2451', '3017', 'c', 'U', '1827', 'V', '8769', '7845', 'K', '3493', 'I', 'Y', '9291', 'u', '6703', '5129', '4485', 'W']

1, 4, 8911, 2451, 3017, 3, 21, 1827, 22, 8769, 7845, 11, 3493, 9, 25, 9291, 21, 6703, 5129, 4485, 23