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: ['H', 'V', 'G', '3251', 'w', 'm', '7129', 'l', 'V', 'j', '521', 'H']

8, 22, 7, 3251, 23, 13, 7129, 12, 22, 10, 521, 8