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: ['3751', '8083', 't', '8407', '2493', '6723', 'L', '4901', '3407', '3151', '9535', '1755']

3751, 8083, 20, 8407, 2493, 6723, 12, 4901, 3407, 3151, 9535, 1755