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

Q: JIOKyo, oPOKsX

A: OK
****
Q: nhGinCtvLartcMPhJwGRbpZNrq, iQJlFKayEartcMPhJwDRROB

A: artcMPhJw
****
Q: mWXTLreV, XMpXTLPRY

A:
XTL
****
