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: ['G', '4571', '5021', '3579', '3909', 'W', '2163', 'n', '3345', 'n', 'U']

7, 4571, 5021, 3579, 3909, 23, 2163, 14, 3345, 14, 21