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: ['R', 'f', 'A', 'd', 'j', 'X', 'h', '3619', '1409', 'T', 't', 'L', '2973', '4995', 'H', 'U', '851', '8613', 'J', 'c', 'I', '4061', 'T', '1645', 'l', '4481', '6543', '4029', 'o', 't', '3775']

18, 6, 1, 4, 10, 24, 8, 3619, 1409, 20, 20, 12, 2973, 4995, 8, 21, 851, 8613, 10, 3, 9, 4061, 20, 1645, 12, 4481, 6543, 4029, 15, 20, 3775