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: ['5855', 'L', '1199', '7917', 'v', '1981', '5447', '4985', 'q', 'O', 'a', 'U', 'D', '823', '8457', 'r']

5855, 12, 1199, 7917, 22, 1981, 5447, 4985, 17, 15, 1, 21, 4, 823, 8457, 18