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

Ex Input:
vMYfFo, EHYfnP

Ex Output:
Yf


Ex Input:
ScUCglVzZFPjLVofNHOumU, mNodEXwpZFPjLVofYfSnBM

Ex Output:
ZFPjLVof


Ex Input:
akkpWuJTMqRGQsSCOdMWm, IGwuIFPaMqRGQsSCOdYKoy

Ex Output:

MqRGQsSCOd