In this task, you are given two strings A, B. Find the longest common substring in the strings A and B.

[Q]: xtCJGe, DXCJSw
[A]: CJ


[Q]: zBxuZfJgYrlRSzkmAktO, YNMgYrlRSzklmBOH
[A]: gYrlRSzk


[Q]: vnRxXLQEyta, JrkrRRxXLQEtIcAI
[A]:
RxXLQE