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: ['6287', '7423', 'G', 'Q', 'F', '9671', '7877', 'Y', '6077', 'm', '4855', 'z']

6287, 7423, 7, 17, 6, 9671, 7877, 25, 6077, 13, 4855, 26