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

Ex Input:
lQwpMQRxuVbJDv, UkzwpMQRxuDVT

Ex Output:
wpMQRxu


Ex Input:
xzMUdHcoYJFWLOILjrg, vCscoYJFWLzO

Ex Output:
coYJFWL


Ex Input:
pGMLEbCPIRyo, csluxOMLEbCPRDau

Ex Output:

MLEbCP