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: ['6543', 'l', 'q', 'c', '8675', 'N', 'm', '135', 'z', 'd', '6019', 'T', 'W', '4751', '6593', '3699', '5823', 'c', 'X', '6863', 'P']

6543, 12, 17, 3, 8675, 14, 13, 135, 26, 4, 6019, 20, 23, 4751, 6593, 3699, 5823, 3, 24, 6863, 16