instruction:
In this task, you are given two strings A, B. Find the longest common substring in the strings A and B.
question:
MSzHyOuaJILkeY, eUibEHoHyOuaJIhfvXy
answer:
HyOuaJI


question:
kvutZfcPKzHE, kTKutZfcPTGmU
answer:
utZfcP


question:
nxTtNYaazlOyEBApiUSJS, BLazlOyEBCV
answer:

azlOyEB