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]: 6, 10, ['P', '6217', 'k', '761', 'L', 'r', '1897', '1503', '7353', '1055', '6661', 'p', 'p', '4313', 'i', 'P', '5081', '3723', 'x', '8455', 'D', 'l', '1379']
[EX A]: 5501353730517981r

[EX Q]: 2, 3, ['U', 'U', '5201', '4581', '2943', 'B', 'j']
[EX A]: 1025U

[EX Q]: 11, 16, ['5629', '9793', '1291', '9539', '8253', 'S', 'U', '2635', '6699', 'W', '2755', '6733', 'd', 'v', '9683', 'q', 'k', '3783', 'T', 'S', '8081']
[EX A]:
q3869vd33765572