instruction:
In this task, you are given two strings A, B. Find the longest common substring in the strings A and B.
question:
PzXzvmYrlGZgOBk, iKnzvmYrlGZgOrs
answer:
zvmYrlGZgO


question:
bmZKWkYPqugcvzbHykblPzQLhK, tPUzKqugcvzbHypzk
answer:
qugcvzbHy


question:
sBNJNfPUdxopcKWbjPtRdpxO, FbUdxopcKWbjlbpFtPvuR
answer:

UdxopcKWbj