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

[EX Q]: jFVaEHbMrrkW, ekfVaEHbPnBnM
[EX A]: VaEHb

[EX Q]: ICizmXnKMpUH, oDrnmXnKgWXX
[EX A]: mXnK

[EX Q]: mZIbWG, BcIbCv
[EX A]:
Ib