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: ['e', '7857', 'v', 'f', 'u', '1899', 'F', 'm', 'r', '3967', '6351', '7407', 'g', '3515', '5375', '621', 'o', '2239', 'm', 'j', 'i', 'I', 'r', '6435', '4887', '5847', '6375', 'w', '6839', '247', 'y', '8993', '1543', '3689', 'Y', '6383', '1401']

5, 7857, 22, 6, 21, 1899, 6, 13, 18, 3967, 6351, 7407, 7, 3515, 5375, 621, 15, 2239, 13, 10, 9, 9, 18, 6435, 4887, 5847, 6375, 23, 6839, 247, 25, 8993, 1543, 3689, 25, 6383, 1401