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

[EX Q]: RinootTGLjbRGYznmBdH, oRMtTGLjbRGYzwEVHsjW
[EX A]: tTGLjbRGYz

[EX Q]: JAGuNgaUudP, eojvKNgaUuQg
[EX A]: NgaUu

[EX Q]: vLOeIJleffCmXtP, hFreIJlefIaLO
[EX A]:
eIJlef