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

yQRDycTycwH, ImycTycrR
ycTyc

faHRBWyXsYzYmHQyy, aHTyXsYzYeXBFV
yXsYzY

uxHsXJpARZcGOJkGA, ufWpARZcGOOz

pARZcGO