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: 4, 9, ['M', 'Q', 'p', 'U', '6315', 'p', 'X', 'U', '3129', 'z', '6667', 'U', 'T', '607', 'J', 'S', 'V', '2757', '7537', 'E', '9739', 'n', '3479', 'R', '159', 'r']

3129UXp6315U