instruction:
In this task, you are given two strings A, B. Find the longest common substring in the strings A and B.
question:
JAGuNgaUudP, eojvKNgaUuQg
answer:
NgaUu


question:
QKlzsmHyBcC, snPtzsmHdMIv
answer:
zsmH


question:
Ipyyudj, bhyyuKXg
answer:

yyu