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

Input: Consider Input: YlhtTQgHiffTbIbBrcHMqFKCdWz, HyregFgMffTbIbBrcHYUnnQvGlx

Output: ffTbIbBrcH


Input: Consider Input: cUCQXEFSgRZjK, RYdvUQXEFSgRZVlwx

Output: QXEFSgRZ


Input: Consider Input: EClIjrcogvyjqKsu, JTsYzjrcogvyWSP


Output: jrcogvy