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

Input: Consider Input: spGRUmIYuGl, qkqRUmItqU

Output: RUmI


Input: Consider Input: GHdeqnuYnQ, zzQeqnutAZ

Output: eqnu


Input: Consider Input: gxWFxVfYebkClR, xCSLFxVfYebByjwf


Output: FxVfYeb


