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: ['7843', '5533', 't', '5305', '6393', '3029', '779', 'T', 'V', '6333', 'n', '4569', 'a', '8127', 'u', 'a', 'D', '771', 'y', 'n', 'B', 'I', '47', 'a', '7471', '1523']

7843, 5533, 20, 5305, 6393, 3029, 779, 20, 22, 6333, 14, 4569, 1, 8127, 21, 1, 4, 771, 25, 14, 2, 9, 47, 1, 7471, 1523