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

FQAznAuFjoBKRKB, hPmtFFPnuAznAuFjoBKTgkeJyjcd
AznAuFjoBK

XpFCxFOgTTNCnQzMnVPV, FMqzdOwgTTNCnQzedorxVPe
gTTNCnQz

zyJadRSftWXUCslXcaH, lgOkgUxSftWXUCsljpk

SftWXUCsl