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', '1671', 'l', 'k', 'X', 'T', 'E', '6027', 'J', '8807', '9391', '2499', '5095', 'U', 'i', 'V', 'I', '2901', 'n', 'q', 'w', 'k', '3697', 'X', '6799', 'n', 'x', 'g', '287', 'H', '5007', '1361', '4571', 'U']

18, 1671, 12, 11, 24, 20, 5, 6027, 10, 8807, 9391, 2499, 5095, 21, 9, 22, 9, 2901, 14, 17, 23, 11, 3697, 24, 6799, 14, 24, 7, 287, 8, 5007, 1361, 4571, 21