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.

[EX Q]: 1, 2, ['S', '7763']
[EX A]: 3677S

[EX Q]: 3, 18, ['R', '7241', 'A', 'z', '8115', '6251', 'F', '1405', 'N', '3567', '1525', 'a', '6057', 'E', '5637', '4969', '3499', '5489', 'Z', 'K', 'M', 'I', 'Z', 'j']
[EX A]: 9845994396947365E7506a52517653N5041F15265118zA

[EX Q]: 7, 12, ['O', 'w', 'D', '2295', 'O', 'Q', '2381', '5427', 'b', 'x', 'd', '2045', 'I', '1905', 'U', '3397', '6911']
[EX A]:
5402dxb72451832