In this task, you are given two strings A, B. Find the longest common substring in the strings A and B.

[EX Q]: PShMbsbexXGlpBuMMDZZS, sVqGxSexXGlpBxuHXoI
[EX A]: exXGlpB

[EX Q]: JqdTDnZqSuSVcMsx, TEtDDnZqSuZa
[EX A]: DnZqSu

[EX Q]: QKnulzCGDXsHd, dylzCGDWo
[EX A]:
lzCGD