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: ['6147', 'm', '4133', 'c', '9397', '5001', '7023', 'U', 'U', '6183', '8895', '7905', '2177', '4031', 'E']

6147, 13, 4133, 3, 9397, 5001, 7023, 21, 21, 6183, 8895, 7905, 2177, 4031, 5