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: ['1859', 'c', 'x', '487', '3781', 'x', '7231', '6117', 'y', 'P', 'S', 'R', '6915', '45', 'V', '8197', '5481', '9613', '5521', 'a', '2941', '9905', 'R', 'R', '7199', 'b', '7641', 'T', '3503', '9923', '9677', 'f', '1505', 'g', 'O']

1859, 3, 24, 487, 3781, 24, 7231, 6117, 25, 16, 19, 18, 6915, 45, 22, 8197, 5481, 9613, 5521, 1, 2941, 9905, 18, 18, 7199, 2, 7641, 20, 3503, 9923, 9677, 6, 1505, 7, 15