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: ['415', '641', '4785', 'r', 'M', '5623', '6421', 'a', '7929', '2789', 't', '571', '8217', '2199', '9235', '5421', '7201', '2161']

415, 641, 4785, 18, 13, 5623, 6421, 1, 7929, 2789, 20, 571, 8217, 2199, 9235, 5421, 7201, 2161