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: ['6007', 'H', 'o', 'S', 'y', '6991', '6553', '201', '6969', '8923', '4861', '3181', 'Y', '5843']

6007, 8, 15, 19, 25, 6991, 6553, 201, 6969, 8923, 4861, 3181, 25, 5843