instruction:
In this task, you are given two strings A, B. Find the longest common substring in the strings A and B.
question:
BmxgSFWBlVX, kGgKrgSFWBlGunFcZ
answer:
gSFWBl


question:
JqdTDnZqSuSVcMsx, TEtDDnZqSuZa
answer:
DnZqSu


question:
HJYjqGBsAuNSnSZJCEAmQJM, zawtvZNouNSnSZJCElWXJDeLV
answer:

uNSnSZJCE