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

Example Input: NUuLSmDjCKcJPc, lGGSLIDjCKcJBo
Example Output: DjCKcJ

Example Input: txJhzNeBj, qLJhzNesV
Example Output: JhzNe

Example Input: LbIzgTzXRwmTqUoNHUEdC, TKnDSWCRXRwmTqUososY
Example Output:
XRwmTqUo