instruction:
In this task, you are given two strings A, B. Find the longest common substring in the strings A and B.
question:
lMRuEThD, wqQRuEKp
answer:
RuE


question:
kWnjCoVmCSVuW, RILPKCoVmCSVbaOza
answer:
CoVmCSV


question:
WIcfzlvE, nNlcfzeFI
answer:

cfz


