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: ['5151', '8663', '4373', 'L', '5491', '123', 'l', 'E', 'b', '3047', 'o']

5151, 8663, 4373, 12, 5491, 123, 12, 5, 2, 3047, 15