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, 21, ['G', '3215', 'y', '3991', 'f', '5813', 'J', '1355', 'J', '2959', 'A', 'i', '2637', 'N', '1973', 'J', 'N', '2269', '7321', 'A', '9997']

9997A73212269NJ1973N2637iA2959J1355J5813f3991y