instruction:
In this task, you are given two strings A, B. Find the longest common substring in the strings A and B.
question:
DhhYhrqVMXSoyvXQwqPKzWARAP, CaMXSoyvXQwqcDDtMsVqD
answer:
MXSoyvXQwq


question:
cZSEmdgP, YsSEmEIM
answer:
SEm


question:
uUrvoj, Ccrvvt
answer:

rv