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: ['H', '1521', '5233', 'I', '8457', '2511', '2883', 'a', 'u', 't', 't', 'k', '1159', 'm', 'y', 'f', '8887']

8, 1521, 5233, 9, 8457, 2511, 2883, 1, 21, 20, 20, 11, 1159, 13, 25, 6, 8887