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

OjQHcFUCflYUptUPqYKVomn, GXHcFUCflYUpSSTrQ
HcFUCflYUp

xtCJGe, DXCJSw
CJ

IxgIJmrEvhpmjVMlkRbbGrN, dxzfVKRARrEvhpmjVMlKRsbdQX

rEvhpmjVMl