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

jLbHvZmecfxMcGLXGVsO, erFBGmecfxMcJtDyKGZ
mecfxMc

XHqQIPw, brqQIkAt
qQI

ynNHHODw, FpENHHIXC

NHH