In this task, you are given two strings A, B. Find the longest common substring in the strings A and B.
--------
Question: FCKbAgSVgj, wAEAWbAgSVSVwD

Answer: bAgSV


Question: ChKUlYUTQQBjZMZkgEed, lmQQBjZMZkgdEf

Answer: QQBjZMZkg


Question: gsqcKomdfZEKXgjGMLvYcJHssR, BRiaCmdfZEKXgjGLj

Answer:
mdfZEKXgjG