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: ['U', '2861', 'R', '4471', 'X', '2377', 'z', '8547', '4365', 'M', 'Z', '9149', 'R', '3995', 'O', '103', '8001', '1351', '6945', '2189', '6711', '4151', '1285', 'b', '4285', 'U', 'E', '3013', '2889', '8145']

21, 2861, 18, 4471, 24, 2377, 26, 8547, 4365, 13, 26, 9149, 18, 3995, 15, 103, 8001, 1351, 6945, 2189, 6711, 4151, 1285, 2, 4285, 21, 5, 3013, 2889, 8145