instruction:
In this task, you are given two strings A, B. Find the longest common substring in the strings A and B.
question:
xzMUdHcoYJFWLOILjrg, vCscoYJFWLzO
answer:
coYJFWL


question:
nWTnWqkLqYTBxT, cSTnWqkLqYwXmxRF
answer:
TnWqkLqY


question:
mnNMgmoQmMcAqLTvu, cEiVgmoQmMcVe
answer:

gmoQmMc