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: ['4915', '8387', 'z', '2905', '9565', 'u', 'C', 'w', '779', 'p', '2955', '111', 'o', '803', '7125', '1923', 'c', '2561', '6787', 'd', '973', '8031', '9979', 'M', 'i', 's', '6583', '901', '4123', 'b', 'h', 'y', 'S']

4915, 8387, 26, 2905, 9565, 21, 3, 23, 779, 16, 2955, 111, 15, 803, 7125, 1923, 3, 2561, 6787, 4, 973, 8031, 9979, 13, 9, 19, 6583, 901, 4123, 2, 8, 25, 19