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

PQCjJwXurLeN, vsjJwXuOy
jJwXu

PIcbiJj, hedcbiZHF
cbi

sBRnoZbIQBPwfvCmERDZj, vrKbIQBPwfvCHymQqkJz

bIQBPwfvC