instruction:
In this task, you are given two strings A, B. Find the longest common substring in the strings A and B.
question:
VRamNL, mUamIB
answer:
am


question:
QjDQjzAIsnYgNmmetl, vyqDQjzAIsnNajYEheP
answer:
DQjzAIsn


question:
joqrPsieTIpltQrDy, xmlYsieTIpRfrBM
answer:

sieTIp