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: ['9007', '1763', '6967', '4893', 'Z', '993', 'M', '8521', 'I', 'Z', '735', 'L', 'M', '1811', 'n', 'S', 'U', 'S', '4891', '3915']

9007, 1763, 6967, 4893, 26, 993, 13, 8521, 9, 26, 735, 12, 13, 1811, 14, 19, 21, 19, 4891, 3915