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: ['2975', 'n', '9423', 'B', '7861', '8421', '6665', '2555', 'w', 'd', '3647', '1837', '3981', '3343', 'D', '7791', 'z', 'D', '2061', '2073', '2989', '2305', '6587', '3909', '1437', '869', '7877', '2997', '9627', 'd', 'G', 'U', '3741', 'f', 'H']

2975, 14, 9423, 2, 7861, 8421, 6665, 2555, 23, 4, 3647, 1837, 3981, 3343, 4, 7791, 26, 4, 2061, 2073, 2989, 2305, 6587, 3909, 1437, 869, 7877, 2997, 9627, 4, 7, 21, 3741, 6, 8