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: ['2087', 'A', 'U', 'A', 'v', '3455', 'I', 'r', 'm', '7271', 'j', '8577', 'r', '6657']

2087, 1, 21, 1, 22, 3455, 9, 18, 13, 7271, 10, 8577, 18, 6657