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.

['b', 'u', 'r', '3453', '1663', 'b', '651', 'R', 'U', 'U', 'a', 'b', '2769', 'C']
2, 21, 18, 3453, 1663, 2, 651, 18, 21, 21, 1, 2, 2769, 3

['9647', '1215', 'e', 'l', '5977', '3441', 'v', 't', 'N', '3491', 'z', 'G', '3173', '2799', 'h', 'U', 'H', 'I', 'I', '2587', 'R', '3647', 'l', 'T', 'X', '3583', 'e', 'a', '4307', 'p', '7961', 'v', '1889', '5961', '8735', 'Z', '3819']
9647, 1215, 5, 12, 5977, 3441, 22, 20, 14, 3491, 26, 7, 3173, 2799, 8, 21, 8, 9, 9, 2587, 18, 3647, 12, 20, 24, 3583, 5, 1, 4307, 16, 7961, 22, 1889, 5961, 8735, 26, 3819

['s', '8421', 'G']

19, 8421, 7