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

vhZuXCsIkQR, YflCuXCsIkLu
uXCsIk

jJSSBmflUyrEMLjSycA, YkmujkSSBmflUyrKKJZ
SSBmflUyr

NbDOlb, EhDOcE

DO