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

[EX Q]: mvIvSzMtYsfVLdaGEmef, wnzMtYsfVLdaKm
[EX A]: zMtYsfVLda

[EX Q]: qMnjlfIsQRtUlPggCpHqu, gfVndMwYDIsQRtUlPgqBJKCX
[EX A]: IsQRtUlPg

[EX Q]: NUuLSmDjCKcJPc, lGGSLIDjCKcJBo
[EX A]:
DjCKcJ