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: ['6915', 'g', '15', '977', '7177', 'f', 'p', '3537', 'S', 'p', '5023', '8579', 'C', 'g', 'u', '8857', '5243', 'W', '8737', 'C', '1845', 'k', 'j', '3575', 'Y', 'G', '8173', '3645', '8457', '1685', 'H']

6915, 7, 15, 977, 7177, 6, 16, 3537, 19, 16, 5023, 8579, 3, 7, 21, 8857, 5243, 23, 8737, 3, 1845, 11, 10, 3575, 25, 7, 8173, 3645, 8457, 1685, 8