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

Example Input: sdGIVJPsWWszKPCGk, ghRJPsWWszKcJUg
Example Output: JPsWWszK

Example Input: jyJrDIhxJtWbnooEXZ, uyXifNCIhxJtWbnVCUrt
Example Output: IhxJtWbn

Example Input: yITbYie, TlqTbYomH
Example Output:
TbY