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: 7, 21, ['4903', 'H', 'q', 'c', 'q', 'S', 'Y', 'm', '6621', '8479', '1581', '5877', '613', 'j', 'a', '8613', 'i', '7381', '5325', 'C', 'L', '8765', 'i', 'R', '6089', '3493', 'D', 'p', 's']

LC53257381i8613aj6135877158184796621mY