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, ['Y', 'R', 'F', 'a', 'y', 'j', 'k', 'R', '2417', '5831', 'a', 'W', '9349', '5931', 'U', 'C', '3', '9409', 'e', '213', '7539', '6927', '9795', '8455', '6013', '5885', 'g', '9757']

7539213e94093CU59319349Wa58312417Rk