instruction:
In this task, you are given two strings A, B. Find the longest common substring in the strings A and B.
question:
XjYkMfARxWBSBjuXyDrFt, EtUxIfiHkMfARxWBSckTLTTnR
answer:
kMfARxWBS


question:
VGRjWGHRcBdFmkVg, eSwqALQXWGHRcBdFsDXCM
answer:
WGHRcBdF


question:
sYWTXbbcGfjZKUNqzPecn, wwdeRHMOyXbbcGfjZKUHhnboc
answer:

XbbcGfjZKU