instruction:
In this task, you are given two strings A, B. Find the longest common substring in the strings A and B.
question:
hCRsCCOoLMpjXwI, lVRCOoLMpxaYFbY
answer:
COoLMp


question:
ZyrpGdXvvtrKQIxU, CLNGdXvvtrKQDpicfqLdt
answer:
GdXvvtrKQ


question:
SeXNqRAbKdLuWXgb, npsIWRAbKdLuUWSbvuS
answer:

RAbKdLu