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: ['3715', 'E', 'K', '5489', '4809', '3643', 'p', 'h', 'o', 'R', 'w', '5239', 'D', '9317', '3137', 'j', '9979', 'a', 'n', '4603']

3715, 5, 11, 5489, 4809, 3643, 16, 8, 15, 18, 23, 5239, 4, 9317, 3137, 10, 9979, 1, 14, 4603