instruction:
In this task, you are given two strings A, B. Find the longest common substring in the strings A and B.
question:
dsngGP, KvnglB
answer:
ng


question:
zRwQdelc, UdAUwQdejhe
answer:
wQde


question:
XiQjqmnEHzsyLeiogbUytTHyJ, jWXEHzsyLeiogVDxzonkTb
answer:

EHzsyLeiog