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

XMtSwZVAHsNYhbyDm, asAVAHsNYhSPuNLrV
VAHsNYh

ugDpSMRvHM, DDwSMRvxw
SMRv

MfvqqCDuD, GlXvqqCmeq

vqqC