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

Ex Input:
tmBlKUto, eFDBlKLy

Ex Output:
BlK


Ex Input:
YPeBvuJXaSLLPhKpUQ, ryjPdyuJXaSLLPhIzBeJP

Ex Output:
uJXaSLLPh


Ex Input:
fnrkEyJiofA, KbSHPrkEyJwdh

Ex Output:

rkEyJ