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

WFAPUCgVYbmZiFlacUzyv, xQFiekrgPUCgVYbmZUEtl
PUCgVYbmZ

osmJJcZlDAXBgJFsJKa, rzPNlDAXBgJYrgXlH
lDAXBgJ

VPwAKYda, uqewAKvXt

wAK