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

DZfOjrQffR, CXOjrQQc
OjrQ

jFVaEHbMrrkW, ekfVaEHbPnBnM
VaEHb

kfvrkXBoQPtYWXRtSqHsum, bbNzIrIEoQPtYWXRtnPBWuEf

oQPtYWXRt