Definition: In this task, you are given inputs i, j, and A, where i and j are integers and A is a list. You need to find all elements of A from the ith element to the jth element, reverse the order in which they occur, and then concatenate them to output the resultant string. i and j will be non-negative, and will always have a value less than the length of A. i will always be less than j. Perform the operations in order, i.e., do not concatenate the elements and then reverse the string.
Input: 4, 20, ['H', '4189', '3945', '8339', 'o', '6807', '8955', '8201', 'H', '1803', '9507', '3671', '6573', 'X', 'J', 'x', '8751', '9333', '3955', '9971', '1981']

9971395593338751xJX6573367195071803H820189556807o8339