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

Example Input: AkYuNemHGBEDF, uluNemHGAycbWX
Example Output: uNemHG

Example Input: hCRsCCOoLMpjXwI, lVRCOoLMpxaYFbY
Example Output: COoLMp

Example Input: YEvyNKXINSl, ffKyNKXFsV
Example Output:
yNKX