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

Q: CdRbREFMEDTXnEzgn, zHLEMMEDTXnEPH

A: MEDTXnE
****
Q: biAihydBoNlzR, IAloNhydBolwUz

A: hydBo
****
Q: NhysWx, hWyszD

A:
ys
****