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

Ex Input:
CdRbREFMEDTXnEzgn, zHLEMMEDTXnEPH

Ex Output:
MEDTXnE


Ex Input:
YlhtTQgHiffTbIbBrcHMqFKCdWz, HyregFgMffTbIbBrcHYUnnQvGlx

Ex Output:
ffTbIbBrcH


Ex Input:
bgvMpDEBwoeAgyzxkDwJ, oqMBsVipDEBwoeAXSWaSQ

Ex Output:

pDEBwoeA


