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: ['6419', 't', 'w', '9231', 'j', 'h', 'F', '6491', 'M', 'F', '4567', 'w', '4775', 'j', '7797', '877', 'N']

6419, 20, 23, 9231, 10, 8, 6, 6491, 13, 6, 4567, 23, 4775, 10, 7797, 877, 14