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:
ylyLVUjsmMrXMFAPDGIZsHq, cYymMrXMFAPjm
answer:
mMrXMFAP


question:
PDwBpXgG, kJBpXevf
answer:

BpX