instruction:
In this task, you are given two strings A, B. Find the longest common substring in the strings A and B.
question:
SIIPePlrkftKkzfgdjg, JqNnXHrkftKkzOMUwmc
answer:
rkftKkz


question:
MSzHyOuaJILkeY, eUibEHoHyOuaJIhfvXy
answer:
HyOuaJI


question:
DxjvJPWGaGCo, LWbPvJPWGThG
answer:

vJPWG