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

[Q]: HhBhJMpxpty, MxTJMpxnQEf
[A]: JMpx


[Q]: dxqZUOvRprXyFfjQfTWBhR, biSVjOvRprXyFfDtuFWQ
[A]: OvRprXyFf


[Q]: oFMeVYMcvKFIIk, AAKYMcvKRgL
[A]:
YMcvK