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: ['6837', 'Z', '5511', 'G', 'M', '1857', 'H', '6651', 'w', 'J', 'R', 'G', 'B']

6837, 26, 5511, 7, 13, 1857, 8, 6651, 23, 10, 18, 7, 2