instruction:
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.
question:
18, 22, ['I', '4687', 'V', 'y', 'U', '2255', '6971', '793', 'W', 'O', '3233', '5061', '6355', 'X', 'U', '8435', 'e', 'z', 'u', '6055', 'd', '1493', 'e', '4453', 'X']
answer:
3941d5506uz


question:
6, 16, ['y', 'M', '5237', '1935', '4057', 'W', '1937', '6517', '717', 'i', '8255', '1011', 'A', '3537', '2411', 'U', 'J', 'a', '1591', '2299', 'W', '8383', '8579', '8183', '7473']
answer:
U11427353A11015528i71771567391W


question:
19, 20, ['W', '6371', '5661', '2061', 'e', '8731', '121', '2097', 'Q', 'R', 'd', 'm', 'c', 'V', 'L', 'U', 'u', 'c', '7543', 'w', '8461', 'L', 'b', 'F', 'D', '4427', 'J', 'b', '4113', 'x']
answer:

w3457