instruction:
In this task, you are given two strings A, B. Find the longest common substring in the strings A and B.
question:
dReySjyqecU, loSjyqiRl
answer:
Sjyq


question:
JIOKyo, oPOKsX
answer:
OK


question:
JDaTrLwAqeDo, pGrLwATk
answer:

rLwA