instruction:
In this task, you are given two strings A, B. Find the longest common substring in the strings A and B.
question:
FNVeaFmprNHqqtAaKv, iGBmrrMveaFmprNHqWWAvtht
answer:
eaFmprNHq


question:
kvutZfcPKzHE, kTKutZfcPTGmU
answer:
utZfcP


question:
eycPrN, bhcPlr
answer:

cP