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: ['B', 'q', 'r', 'd', 's', '6415', '2763', 'p', '5739', 'W']

2, 17, 18, 4, 19, 6415, 2763, 16, 5739, 23