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

rPPfxUdowLLdvwRtY, PuHovApkfxUdowLLBOhq
fxUdowLL

mJoHBJehHtkFS, ZMrDxHBJehHtxS
HBJehHt

oIZIIxgolTKu, eFVruIIxgoleYlTuZ

IIxgol