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: ['9519', '1781', '3821', '1405', 't', '6731', 'y', '8181', 'g', 'T', '9207', '6301', '4005', 'C', 'o']

9519, 1781, 3821, 1405, 20, 6731, 25, 8181, 7, 20, 9207, 6301, 4005, 3, 15