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

egYXVtCPvWxP, VMOolyVtCPvWjIx
VtCPvW

SFQHJlK, dHfQHJoUC
QHJ

XXmkHCaYxDPnOwBSykupK, BhYhCaYxDPnOwINgrcDnrV

CaYxDPnOw