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:
2, 3, ['X', '8243', '1209']
answer:
90213428


question:
1, 1, ['f', 'E', 'G', '9657']
answer:
f


question:
19, 22, ['r', 'b', '8781', '1205', 'C', '4201', 'y', 'L', '9799', 'B', 'C', '4029', '3951', 'm', '4761', '8023', '99', '3337', '8049', '5887', '8493', '687', '3893']
answer:

786394878859408