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

XZslQqrShfCXRXyHrFVq, BtOQgQqrShfCXRRCRbMvXPM
QqrShfCXR

QlJnxO, BLJnCQ
Jn

kJPHoreuoYXqlYMmD, PlVDTBnHoreuoYXqlmfdUYnaRBZ

HoreuoYXql