instruction:
In this task, you are given two strings A, B. Find the longest common substring in the strings A and B.
question:
jJSSBmflUyrEMLjSycA, YkmujkSSBmflUyrKKJZ
answer:
SSBmflUyr


question:
nrIHKzJCdAQzUDRBYpg, JDzJCdAQzUMMYrLcfO
answer:
zJCdAQzU


question:
rtxzGUltDHFXnLxbEGnGea, ukdJRzGUltDHFXnSNkHV
answer:

zGUltDHFXn