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

GlAYDsKQoXy, IxDsKQuK
DsKQ

dxqZUOvRprXyFfjQfTWBhR, biSVjOvRprXyFfDtuFWQ
OvRprXyFf

jAinxmaQUrmu, jqeEnxmaQUrWlrEqW

nxmaQUr