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: ['499', '8491', '6423', 'd', '7715', 'Z', '9615', 'I', '4873', '2291', 'l', 'Y', 'l', '2095', '4015', 'V', 'S']

499, 8491, 6423, 4, 7715, 26, 9615, 9, 4873, 2291, 12, 25, 12, 2095, 4015, 22, 19