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: 3, 20, ['U', 'N', '4009', 'B', 'H', 'f', 'h', '1703', 'u', '7141', 'u', 'K', '135', 'b', 'l', 's', '2013', '2785', '2047', '2001', 'w', 'v', '6957', '241']

2001204727852013slb135Ku7141u1703hfHB4009