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]: 3, 21, ['V', '3661', '3743', 'Y', '3179', 'b', '7097', '3031', '5859', '4095', 'D', 'J', '2337', '4259', '2539', 'I', '9659', 'U', 'G', 'Q', '3145', '177', '9839', 'f']
[EX A]: 5413QGU9569I935295247332JD5904958513037907b9713Y3473

[EX Q]: 12, 12, ['c', 'a', 'G', 't', '753', 'x', 'I', '4479', 'i', 'y', 'J', 'w']
[EX A]: w

[EX Q]: 1, 4, ['9085', 'f', '991', '9109', 'T', '4481', '3649', 'f', 'b', 'C', 'K', '9307', 'K', 'H', '7283', 'Q', 'A']
[EX A]:
9019199f5809