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: 13, 20, ['699', 'W', 'L', 'g', '9023', 'H', 'N', '7089', '113', '1145', '3031', 'y', 'k', '1395', '7989', '2845', '4693', 'U', 'K', 'R', '9129']

RKU4693284579891395k