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: ['6291', '4309', 'e', '3333', '8283', '9959', 'a', 'Y', 'E', 'c', 'N', 'k', 'o', 'j', 'z']

6291, 4309, 5, 3333, 8283, 9959, 1, 25, 5, 3, 14, 11, 15, 10, 26