instruction:
In this task, you are given two strings A, B. Find the longest common substring in the strings A and B.
question:
ahPbomjSH, rBbomynK
answer:
bom


question:
QaxEaxdouNyyvNAn, wRjWSaxdouNyyrriQiG
answer:
axdouNyy


question:
LQpsVr, cYpsIY
answer:

ps