instruction:
In this task, you are given two strings A, B. Find the longest common substring in the strings A and B.
question:
lypuwWy, jRpuwcE
answer:
puw


question:
hCRsCCOoLMpjXwI, lVRCOoLMpxaYFbY
answer:
COoLMp


question:
oFPAQJpWaqjIwXXL, KtFyAQJpWaqjIImedePddh
answer:

AQJpWaqjI