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

haOsaSQcyodWhqQaC, BKLEUQcyodWhvVkmxBz
QcyodWh

oZNKLmfxecDfkXEGFkRBYk, tReqkiExecDfkXEGtNZpJVRxC
xecDfkXEG

lgKYEuXjJ, DXlUKYEuZIFp

KYEu