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

Ex Input:
WFAPUCgVYbmZiFlacUzyv, xQFiekrgPUCgVYbmZUEtl

Ex Output:
PUCgVYbmZ


Ex Input:
hcmMoVBhK, mdmMoVBjuT

Ex Output:
mMoVB


Ex Input:
tSMNbIWzDiLyFaKg, hoGcvbIWzDiLyzvwRm

Ex Output:

bIWzDiLy