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: ['2573', 'g', '4703', '4231', 'T', '3409', '4149', '3969', 'N', '6539', 'L', 'u', '1783', '3515', '7495', 'f', 'O', 'r', 'P', 'h']

2573, 7, 4703, 4231, 20, 3409, 4149, 3969, 14, 6539, 12, 21, 1783, 3515, 7495, 6, 15, 18, 16, 8