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: ['6459', 'U', '8907', 'j', 'y', 'B', 'u', 'o', 'l', '8333', 'P', '5817', 'n', '1277', '7', 'j', 'P', 'b', '7811', 'r', '7903', 'Z', 'j', '4559', 'Y', 'z', '6695', '9701', 'I', 'M', '4355', 'V', 'H', '575', 'Y', '1369', 'x']

6459, 21, 8907, 10, 25, 2, 21, 15, 12, 8333, 16, 5817, 14, 1277, 7, 10, 16, 2, 7811, 18, 7903, 26, 10, 4559, 25, 26, 6695, 9701, 9, 13, 4355, 22, 8, 575, 25, 1369, 24