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

bmZKWkYPqugcvzbHykblPzQLhK, tPUzKqugcvzbHypzk
qugcvzbHy

bmsrkXGb, GcarkXOZF
rkX

ymbmDzLTIYrAO, SgcIDzLTIkb

DzLTI