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: ['A', '1567', '8545', '6999', '9121', 'G', 'P', 'Z', 't', '6573', 'x', 't', 'w', '4347', '2639', '887', '3917']

1, 1567, 8545, 6999, 9121, 7, 16, 26, 20, 6573, 24, 20, 23, 4347, 2639, 887, 3917