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

umXfmRnUgALpFAqBaKfNfo, aOAXWnUgALpFAqBmNpTCdj
nUgALpFAqB

yRhCObvPZYoKUoQnyaatR, NHzLJYPZYoKUoQnJnIsZxC
PZYoKUoQn

yVPDmugdAC, ZFKwDmugsFTn

Dmug