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: ['6773', 'z', 'T', 'p', 'U', '993', '2883', '6921', '8821', '4685', 'B', 'J', '8251', 'H', '103']

6773, 26, 20, 16, 21, 993, 2883, 6921, 8821, 4685, 2, 10, 8251, 8, 103