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: ['2543', 'X', 'G', 'k', 'E', 'x', '3983', '3723', '8171', 'F', 'M', '9881', 'R', 'Z', 'E', '8607', 'T', 'n', '321', '8391', 'u', '3045']

2543, 24, 7, 11, 5, 24, 3983, 3723, 8171, 6, 13, 9881, 18, 26, 5, 8607, 20, 14, 321, 8391, 21, 3045