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

Ex Input:
trHTzJpm, aCHTzVVA

Ex Output:
HTz


Ex Input:
sJRFPufsaWXNeu, AePufsafc

Ex Output:
Pufsa


Ex Input:
sXLtvIpVYCNak, TZtApIpVYCdw

Ex Output:

IpVYC