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: ['2875', '7021', '4059', 'G', 'W', '3619', 'F', '3787', '153', 'x', 'v', 'x', '6417', '4507', 'Y', 'D', 'U', '4083']

2875, 7021, 4059, 7, 23, 3619, 6, 3787, 153, 24, 22, 24, 6417, 4507, 25, 4, 21, 4083