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

iupYjFXrrMqWzJSLUSwmEukHc, hqajjWrrMqWzJSLnF
rrMqWzJSL

MSzHyOuaJILkeY, eUibEHoHyOuaJIhfvXy
HyOuaJI

PElAQv, AolAfa

lA