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: ['3515', '5271', '4907', '4935', '7597', '5125', 'g', '8455', 'j', 'Y', '4277', '9577', 'W', '5615', 'u', 'r', '5171']

3515, 5271, 4907, 4935, 7597, 5125, 7, 8455, 10, 25, 4277, 9577, 23, 5615, 21, 18, 5171