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: ['7517', '3553', 'L', 'd', '5791', '4847', 'l', 'r', '5981', 'l', '7285', 'l', '2093', 'B', 'o', 'T', '2173', '2117', '2011', '7435', '5821', 'Z', '457', '1771', '47', 'g', '4401']

7517, 3553, 12, 4, 5791, 4847, 12, 18, 5981, 12, 7285, 12, 2093, 2, 15, 20, 2173, 2117, 2011, 7435, 5821, 26, 457, 1771, 47, 7, 4401