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

Ex Input:
tyVlHfTPLRSdFilXnSfqQ, bkTPLRSdFiMgXC

Ex Output:
TPLRSdFi


Ex Input:
pJqqIW, Ivqqxw

Ex Output:
qq


Ex Input:
uBnkIyg, jKnkIde

Ex Output:

nkI