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: ['5809', '4105', 's', '1301', '6439', '8959', 't', '3921', 'U', '3577', 'N', 'r', '4451', '3685', '6801', '3883', 'I', '3793', '521', 'b', '7527', 'o', '483', 'O', '6261', 's']

5809, 4105, 19, 1301, 6439, 8959, 20, 3921, 21, 3577, 14, 18, 4451, 3685, 6801, 3883, 9, 3793, 521, 2, 7527, 15, 483, 15, 6261, 19