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: ['Y', 'Z', 'o', '2471', 'd', 'f', 'U', '5617', 's', '7411', 't', '6019']

25, 26, 15, 2471, 4, 6, 21, 5617, 19, 7411, 20, 6019