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: ['O', '1363', 'I', '4767', '7769', '4607', '8453', 'm', '3607', 'Z', 'k', '2153', 'P', '4215', 'N']

15, 1363, 9, 4767, 7769, 4607, 8453, 13, 3607, 26, 11, 2153, 16, 4215, 14