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

XWKEpwGRkfCFZGOyZQOoypx, lhQkmVqeRkfCFZGOyugPLqs
RkfCFZGOy

OYERnjubLFovtcS, FngzQJVGERnjubLFafmzq
ERnjubLF

TiNWqIoJFeiZf, MLeNWqIoJSfd

NWqIoJ