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

vISTrmBMpQyanUTSXUCm, dJGyOHMpQyanUTpSb
MpQyanUT

oWwqraAz, uxTqraonu
qra

REDrOgVsLVfxfJVTjdWFpJaGmE, pzpuwNfxfJVTjdWFxGRzTfPw

fxfJVTjdWF