instruction:
In this task, you are given two strings A, B. Find the longest common substring in the strings A and B.
question:
sRpnJlgECTHh, JXfmNJlgECKyry
answer:
JlgEC


question:
iwSQnplQZFbXQ, lHWnplQZFzswgU
answer:
nplQZF


question:
kvUvRVxo, ewIvRVzR
answer:

vRV