instruction:
In this task, you are given two strings A, B. Find the longest common substring in the strings A and B.
question:
biAihydBoNlzR, IAloNhydBolwUz
answer:
hydBo


question:
VTwtMVKmrRvL, WLoVtWtMVKmrDCke
answer:
tMVKmr


question:
uRHhYZIgU, xWBHhYZTGx
answer:

HhYZ