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: ['9855', 'K', 'l', '9887', '3421', 'T', 'G', '1611', 'o', '55', 'F', '1667', 'R', '7525', '6091', 'I']

9855, 11, 12, 9887, 3421, 20, 7, 1611, 15, 55, 6, 1667, 18, 7525, 6091, 9