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: ['3977', 'S', '4387', '6833', '7587', '879', '8493', '4837', '4191', '5637', '9953', 'I', '3309', '7481']

3977, 19, 4387, 6833, 7587, 879, 8493, 4837, 4191, 5637, 9953, 9, 3309, 7481