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

wYhGWdRC, cFGWdHEy
GWd

xzMUdHcoYJFWLOILjrg, vCscoYJFWLzO
coYJFWL

TizkNtJUPHfhmGQ, enzehVkNtJUPHunpG

kNtJUPH