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: ['S', '6687', '7821', 'A', 'A', 'o', 'c', '8211', '911', 'L', 'x', '2377', '7699', 'z']

19, 6687, 7821, 1, 1, 15, 3, 8211, 911, 12, 24, 2377, 7699, 26