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', '5573', '7669', '6989', 'a', '731', '7747', 'U', '6599', '549', 'd', '6193', 'y', '4005', '7097', 'C', '5707', '3791', '9671']

5, 5573, 7669, 6989, 1, 731, 7747, 21, 6599, 549, 4, 6193, 25, 4005, 7097, 3, 5707, 3791, 9671