In this task, you are given inputs 'i', 'j', and A, where 'i' and 'j' are integers and A is a list. A list is shown by two brackets and comma-separated numbers and characters inside, like ['1', '12', 'l']. You need to concatenate all elements of A from the ith element to the jth element, and then reverse the resulting 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 reverse first and then concatenate.
19, 21, ['S', '2953', 'M', 'R', '8183', 'G', '5421', 'f', '5809', '8109', '6913', 'q', '9325', '685', 'M', 'b', 'b', '435', '449', 'e', 'L', 'I', '6473']