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', '9385', '6983', 'd', '381', 'm', '1331', 'V', 'U', 'G', 'o', '9309', 'U', '9615', '9261', '2959', 'G', '6059', 'i', '7563', '2729', 'W', '7847', '4075', '1409', 'W', '8731', '643']

21, 9385, 6983, 4, 381, 13, 1331, 22, 21, 7, 15, 9309, 21, 9615, 9261, 2959, 7, 6059, 9, 7563, 2729, 23, 7847, 4075, 1409, 23, 8731, 643