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: 1, 20, ['6339', 'u', '8137', '8729', '4665', 'J', 'y', 'Z', 'n', 'h', '4147', '7199', 'C', 't', '5079', '9017', '7821', '3917', 'O', 'R', 'G', '8463', 'n', 'm']

RO3917782190175079tC71994147hnZyJ466587298137u6339