instruction:
In this task, you are given two strings A, B. Find the longest common substring in the strings A and B.
question:
mCxQTIaXN, mWQTIaxzPT
answer:
QTIa


question:
yOGvgtAmwMwcIRtJ, cQtAmwMwcIRjfjO
answer:
tAmwMwcIR


question:
JmtPHpukIQJjuc, whPHpukIaRnJh
answer:

PHpukI