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: 15, 21, ['2279', '3249', 'u', '7055', 'Q', '111', '5711', 'p', 'Q', '6269', 'Q', '2791', 'O', 'q', '6293', 'U', '7887', 'P', '2521', 'd', 'X', '4215', 'J', 'I', '7703']

Xd2521P7887U6293