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: ['B', 'i', '9515', 'E', 'O', '479', '347', '8093', 'r', '6243', '419', 'm', 'd', 'F', '8213', '5575', 'E', 'P', 'N', '723', 'm', '3387', '5223', 'T', '477', '2623', 'U', '6907']

2, 9, 9515, 5, 15, 479, 347, 8093, 18, 6243, 419, 13, 4, 6, 8213, 5575, 5, 16, 14, 723, 13, 3387, 5223, 20, 477, 2623, 21, 6907