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: ['6249', '4881', 'T', 'l', 'B', '2291', '7235', 'f', '9141', '2367', '8295', '5079', 'Z', 'U', 'C', 'i', '6317', 'W', '7473', '2889', 'B', 'r', '4771', '1617', 'E', '8635', '4331', 'c', '3301', '9981']

6249, 4881, 20, 12, 2, 2291, 7235, 6, 9141, 2367, 8295, 5079, 26, 21, 3, 9, 6317, 23, 7473, 2889, 2, 18, 4771, 1617, 5, 8635, 4331, 3, 3301, 9981