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: ['5209', 'd', 'C', 'x', '851', 'M', '8489', '9989', '6033', 'L', 'E', '9201', 'u', 'h', '1279', '9283', '9873', '259', '5015', '9735', 'R', 'J', '637', '4785', 'E', '4893', 'K', 'O']

5209, 4, 3, 24, 851, 13, 8489, 9989, 6033, 12, 5, 9201, 21, 8, 1279, 9283, 9873, 259, 5015, 9735, 18, 10, 637, 4785, 5, 4893, 11, 15