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: ['f', 'r', '6671', '6965', 'O', '4937', 'o', 'w', '2891', '6529']

6, 18, 6671, 6965, 15, 4937, 15, 23, 2891, 6529