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, 21, ['2369', '9675', '2687', 'X', '5187', '1899', 'u', '3423', '5225', 'H', '3061', 'b', '4919', 'd', 'K', '6529', '3775', '6533', 'F', 'I', '8393', '5979']

8393IF653337756529Kd4919b