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: ['7877', 'u', '3171', '9247', '6557', '3559', 'i', 'g', '81', 'L', '621', 'v', '525', 'p', '4751', '6813', 'a', '199', '9287', '6225', '3909', '4761', '3953', 'b', 'w', '7383', '6121', '8753', 'R', 'e', 'H', '4001', 's', '2239', '1499', '2979', '667', 's']

7877, 21, 3171, 9247, 6557, 3559, 9, 7, 81, 12, 621, 22, 525, 16, 4751, 6813, 1, 199, 9287, 6225, 3909, 4761, 3953, 2, 23, 7383, 6121, 8753, 18, 5, 8, 4001, 19, 2239, 1499, 2979, 667, 19