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

spUbdWDLWCeqr, vIuHkWDLWCQEPaz
WDLWC

EJZYVxgFxPoOSDlLfK, uTLTIETHZYVxgFxPoPwr
ZYVxgFxPo

sdGIVJPsWWszKPCGk, ghRJPsWWszKcJUg

JPsWWszK