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

Input: Consider Input: VLxrvK, gvxrac

Output: xr


Input: Consider Input: YRNpKFPGzUsgCOBJgbVG, TdEpMngFPGzUsgCOZykYRrLp

Output: FPGzUsgCO


Input: Consider Input: vGcpqithrXJfiBIXOTkDG, XbOpqithrXJfiUMkGFmPQY


Output: pqithrXJfi