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

Example Input: ScUCglVzZFPjLVofNHOumU, mNodEXwpZFPjLVofYfSnBM
Example Output: ZFPjLVof

Example Input: apGMPThLTCw, LvMPThYW
Example Output: MPTh

Example Input: cJqpVpWvyF, vgepVpWMFFX
Example Output:
pVpW

