instruction:
In this task, you are given two strings A, B. Find the longest common substring in the strings A and B.
question:
TnbLNKnNSs, NhDLNKnNRd
answer:
LNKnN


question:
wbdHVigIkjNkuAmbr, iSgIkjNkQYyn
answer:
gIkjNk


question:
VDCNzkqsAKQwnPTqjkQfQoj, SLQBTxIWAKQwnPTqWYusnF
answer:

AKQwnPTq