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: ['5401', 'P', '3623', '4935', 'd', '2923', '5623', 'H', '9941', 'L', 'k', 'l', 'F', '4821', '1981', '4785', '2451', 'q', 'U', '4923', 'b', '1859', '7967', '857', 'T', 'N', 'p', 'U', 'z']

5401, 16, 3623, 4935, 4, 2923, 5623, 8, 9941, 12, 11, 12, 6, 4821, 1981, 4785, 2451, 17, 21, 4923, 2, 1859, 7967, 857, 20, 14, 16, 21, 26