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

Ex Input:
XjYkMfARxWBSBjuXyDrFt, EtUxIfiHkMfARxWBSckTLTTnR

Ex Output:
kMfARxWBS


Ex Input:
IJQqdzqdaGEIcdyh, izlVdzqdaGGiPYz

Ex Output:
dzqdaG


Ex Input:
XpFCxFOgTTNCnQzMnVPV, FMqzdOwgTTNCnQzedorxVPe

Ex Output:

gTTNCnQz