instruction:
In this task, you are given two strings A, B. Find the longest common substring in the strings A and B.
question:
MSxTzCpiJAplpzSvLlNJS, oScCpiJAplpNVrqkn
answer:
CpiJAplp


question:
DZfOjrQffR, CXOjrQQc
answer:
OjrQ


question:
ckMhFY, YmMhLI
answer:

Mh