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: 12, 20, ['T', '4487', 'm', 'M', '6289', '1759', 'l', '3483', '4459', 'O', '9895', 'u', '5417', 'r', 'B', '2873', '1189', '3837', 'x', '5437']

5437x383711892873Br5417u