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

Q: CzkPtkpMTDeNZwCPbJJn, HzpMVDeNZwCPbJVOU

A: DeNZwCPbJ
****
Q: ARGchkRez, kUwchkZPE

A: chk
****
Q: QYAFcbMCohYT, WlZcbMCoWKpGM

A:
cbMCo
****