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: ['Y', '6859', 'F', 'g', 'J', 'G', '8469', 'l', 'o', '1651', '1229', 'U', '9265', '4195', 'W', '4739', '4629', 'P', 'C', '1833', 'M', 'E']

25, 6859, 6, 7, 10, 7, 8469, 12, 15, 1651, 1229, 21, 9265, 4195, 23, 4739, 4629, 16, 3, 1833, 13, 5