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

EPUxsZtt, KgxsZuXM
xsZ

VRXUhOYfTul, JqZUhOYKq
UhOY

XMqVLPlMVFUTCiYdOBQ, ogpCDucTVLPlMVFUzsgnVq

VLPlMVFU