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: ['4183', '5929', 'J', '261', '313', '555', 'E', '7273', '9349', 'E', 'E', '5707', '3533', '3967', 'J', 'H', 'M', 'x', 'z', '999', 'e', 't', '291', 'J', '1859', '3373']

4183, 5929, 10, 261, 313, 555, 5, 7273, 9349, 5, 5, 5707, 3533, 3967, 10, 8, 13, 24, 26, 999, 5, 20, 291, 10, 1859, 3373