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: ['B', '4187', 'n', '2457', 'o', '1937', '8821', '3821', '7365', 'Z', '7507', '8915', '4233', 'O', 'x', 'n', 'x', 'D', '43', 'K', '4561', '3903', 'U', '1965', '4611', '5857', '4657', '5839', 'P', 'a', 'H', '2497', 'b', '3', '3311', '7639', 'X', '2193', '7553']

2, 4187, 14, 2457, 15, 1937, 8821, 3821, 7365, 26, 7507, 8915, 4233, 15, 24, 14, 24, 4, 43, 11, 4561, 3903, 21, 1965, 4611, 5857, 4657, 5839, 16, 1, 8, 2497, 2, 3, 3311, 7639, 24, 2193, 7553