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

Example Input: HiEuutntEBpU, fdkqEuutntEBABdGZRND
Example Output: EuutntEB

Example Input: ssKUiWgGqsXYlFOOc, JDcVTmCgGqsXYlxYE
Example Output: gGqsXYl

Example Input: mVFJPHAtGlRkW, FlomCyJPHAtGlRAad
Example Output:
JPHAtGlR