instruction:
In this task, you are given two strings A, B. Find the longest common substring in the strings A and B.
question:
QaxEaxdouNyyvNAn, wRjWSaxdouNyyrriQiG
answer:
axdouNyy


question:
nTAXUw, OWAXYU
answer:
AX


question:
jdzLjxwqOxbNmbopB, PJKfEwqOxbNZZz
answer:

wqOxbN