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

Example Input: bUcuzFgsdfojVR, IdcuzFgsdMRgtMA
Example Output: cuzFgsd

Example Input: EOwHDdhJcP, DrIuDdhJYw
Example Output: DdhJ

Example Input: yXUxHT, ENUxgW
Example Output:
Ux