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: ['E', '7029', '3039', 'Z', '4377', 's', 'u', '209', '5071', 'm', '8821', 'E']

5, 7029, 3039, 26, 4377, 19, 21, 209, 5071, 13, 8821, 5