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

ezVsFayUPcrte, lfsFayUMPTqx
sFayU

UtUSmsOI, dCUSmGoQ
USm

xWhShXSBUmDahcYZU, biNnxRSBUmDaQvbqgC

SBUmDa