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

sRTQgRgRUjEooapKdR, vzsBgRUjEooLBkYeH
gRUjEoo

ktABEFESAVHZkkY, uMjxiESAVHZkZgWUte
ESAVHZk

hfTMWfCaePWFPEV, UcWRAfCaePWFPhQyZRQ

fCaePWFP