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: ['i', 'I', 'Y', 'n', '4535', 'N', 'c', 'V', 'x', 'r', 'R', '4413', '1371', '6541']

9, 9, 25, 14, 4535, 14, 3, 22, 24, 18, 18, 4413, 1371, 6541