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

Ex Input:
ksRxEVrz, cOMRxEViwF

Ex Output:
RxEV


Ex Input:
uZSRkFDHsGXNMaggxUn, lTrQKKpsGXNMaggEdSrEX

Ex Output:
sGXNMagg


Ex Input:
NgilTjDOVPw, HjsyilTjDOVEqqHzNv

Ex Output:

ilTjDOV