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.
18, 21, ['1329', 'L', '6345', '6123', 'z', 'J', 'e', 'G', 'q', 'O', '8393', '9641', 'n', '1139', '6195', '4407', 's', 'j', '9073', '9755', '131', 'c', '4481', '6699', 'm']