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: ['D', '5531', '769', '8683', '257', '5991', 'S', 'P', '6511', '5921', 'h', '7583', 'x', '6961', '8049', '8497', 'B', 'D']

4, 5531, 769, 8683, 257, 5991, 19, 16, 6511, 5921, 8, 7583, 24, 6961, 8049, 8497, 2, 4