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: ['U', '3925', 'Y', 'N', 'U', 'w', 'J', 'w', 'R', '9457', '4143', 'y']

21, 3925, 25, 14, 21, 23, 10, 23, 18, 9457, 4143, 25