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: ['6721', 'H', 'C', 'x', 'B', '3167', '6565', '5399', 'M', 'p', 'V', 'O', 'r', 't', 'x', 'z', '1375', 'h', '2271', 'w', 'B', '8771', '1015', 'g', '2889', '7501', 'N', 'v', '4709', 'j', 'B', 'w', 'W', '5045', '3291', 'F', '6299', 'u', '3347', '2199']

6721, 8, 3, 24, 2, 3167, 6565, 5399, 13, 16, 22, 15, 18, 20, 24, 26, 1375, 8, 2271, 23, 2, 8771, 1015, 7, 2889, 7501, 14, 22, 4709, 10, 2, 23, 23, 5045, 3291, 6, 6299, 21, 3347, 2199