instruction:
In this task, you are given two strings A, B. Find the longest common substring in the strings A and B.
question:
RwqzMTeLMdPx, qaWtYhqzMTeLMdHbWDT
answer:
qzMTeLMd


question:
HSsyZzZLZAAq, MFEZzZLJC
answer:
ZzZL


question:
goLYLzTHhbNEA, vHksYLzTHhgKY
answer:

YLzTHh