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

PIcbiJj, hedcbiZHF
cbi

tGBRASi, QABRAtL
BRA

AUQFlFHvMsbnIKKGjceH, dlKCvQFlFHvMsbufxXYXoVU

QFlFHvMsb