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

yhhzISsXKEbA, KlPrazISsXKzmrVBG
zISsXK

XZslQqrShfCXRXyHrFVq, BtOQgQqrShfCXRRCRbMvXPM
QqrShfCXR

AVeyYtICmEK, IQYtICwpl

YtIC