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: ['G', '1751', 'J', 'P', 'C', '199', '881', 'G', '7129', '4613', '2341', '8121', 'p', 'Q', '7991', 'y', 'e', 'f', 'i']

7, 1751, 10, 16, 3, 199, 881, 7, 7129, 4613, 2341, 8121, 16, 17, 7991, 25, 5, 6, 9