instruction:
In this task, you are given two strings A, B. Find the longest common substring in the strings A and B.
question:
wNiHcaiUPHnjp, aSTmjcaiUPHFzOu
answer:
caiUPH


question:
YRNpKFPGzUsgCOBJgbVG, TdEpMngFPGzUsgCOZykYRrLp
answer:
FPGzUsgCO


question:
JSQNaNYUxKYHUl, qXqZPQqaNYUxKYcT
answer:

aNYUxKY