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

Q: yhhzISsXKEbA, KlPrazISsXKzmrVBG

A: zISsXK
****
Q: CdRbREFMEDTXnEzgn, zHLEMMEDTXnEPH

A: MEDTXnE
****
Q: LPtQUMCkHVyvOMrzVEMs, nteBCkHVyvOcD

A:
CkHVyvO
****