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: 6, 18, ['D', '3121', 'p', 'n', '2621', '8697', '4857', 'G', 'D', 'n', 'M', 'H', '67', 'x', '3051', '6327', 'q', '6865', 'U', '7687', '7823', 'R', '3551', 'x', 'l', 'q', '943', 'S']

6865q63273051x67HMnDG48578697