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: ['R', '8541', '2621', 'h', '4337', 'I', 'r', '3123', '4199', 'a', '7637', '5239', 'Z', '9131', '3229']

18, 8541, 2621, 8, 4337, 9, 18, 3123, 4199, 1, 7637, 5239, 26, 9131, 3229