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', '6333', 'e', '3025', 'm', 'L', '9387', '213', 'r', '919', 'c', '5467', 'R', 'l', 'x', '6303', '5423', '2871', 'x', 'e', 'u', '1655', 'F', '5721', 'W', 'K', 'c', '241', '1059', '1547', 'o', '1949', '6837', 'U']

1, 6333, 5, 3025, 13, 12, 9387, 213, 18, 919, 3, 5467, 18, 12, 24, 6303, 5423, 2871, 24, 5, 21, 1655, 6, 5721, 23, 11, 3, 241, 1059, 1547, 15, 1949, 6837, 21