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: 12, 21, ['a', '2479', 'p', '3835', '6431', '1407', '7831', 'E', 'l', 'w', '2121', 't', '3221', '7653', 'U', '8029', 'Z', 'Z', 'H', '2647', '2667']

26672647HZZ8029U76533221t