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: ['C', '2115', '2453', 'p', '9871', 'n', 'a', 'H', 'K', 'x', '2105', 'V', '2807', '8845', '7527', '3787', 'v', '6291', 'y', '2555', '371', 'w', 'R', 't', '7393', 'b', '9619', '3837', '1915', 'l', '9005', 'x', 'd', 'I', 'u', 'i', 'O', 'U']

3, 2115, 2453, 16, 9871, 14, 1, 8, 11, 24, 2105, 22, 2807, 8845, 7527, 3787, 22, 6291, 25, 2555, 371, 23, 18, 20, 7393, 2, 9619, 3837, 1915, 12, 9005, 24, 4, 9, 21, 9, 15, 21