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: ['687', '9407', 'B', 'v', '3947', '1681', 'u', '3401', 'I', '9125', 'y', '7463', 'e', 'R', 'x', '1099', 'q', 'm', 'N', '1821', '8209', '6289', 'i', '619', '4917', '4865', '2405', 'e', '683', 'a', 'e', 'X']

687, 9407, 2, 22, 3947, 1681, 21, 3401, 9, 9125, 25, 7463, 5, 18, 24, 1099, 17, 13, 14, 1821, 8209, 6289, 9, 619, 4917, 4865, 2405, 5, 683, 1, 5, 24