instruction:
In this task, you are given two strings A, B. Find the longest common substring in the strings A and B.
question:
wCfNCfxvLRAxBstRTwMSqTn, AhwxfFNCfxvLRAxBrNtf
answer:
NCfxvLRAxB


question:
wrVsKN, mOVsWo
answer:
Vs


question:
GJOQVmJiYyYEnpT, TzmdCgOQVmJiYyYEZfmfoN
answer:

OQVmJiYyYE