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

[EX Q]: ssKUiWgGqsXYlFOOc, JDcVTmCgGqsXYlxYE
[EX A]: gGqsXYl

[EX Q]: YlhtTQgHiffTbIbBrcHMqFKCdWz, HyregFgMffTbIbBrcHYUnnQvGlx
[EX A]: ffTbIbBrcH

[EX Q]: DAVnsujZTAEZJ, KGnsujZoo
[EX A]:
nsujZ