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

Ex Input:
OYERnjubLFovtcS, FngzQJVGERnjubLFafmzq

Ex Output:
ERnjubLF


Ex Input:
QECPAHsg, bUfPAHOWb

Ex Output:
PAH


Ex Input:
RKPcmixUsXJGxX, mwpWSPPcmixUsDqkhQ

Ex Output:

PcmixUs