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: ['6821', 'D', 'I', '6429', '8651', '8229', 'Y', 'K', 'o', '3905', '2533', '6949', 'j', 'e', 'Y', '1677', '1863', '767', '5135', '7207', 'E', '9793']

6821, 4, 9, 6429, 8651, 8229, 25, 11, 15, 3905, 2533, 6949, 10, 5, 25, 1677, 1863, 767, 5135, 7207, 5, 9793