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

Input: Consider Input: TnHJcxtwcZ, XFdHJcxNKw

Output: HJcx


Input: Consider Input: koIZvrJmfKCO, TBvrtjcWIZvrJmfKRZDOE

Output: IZvrJmfK


Input: Consider Input: VftkwG, ottknT


Output: tk