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:
nTAXUw, OWAXYU

Ex Output:
AX


Ex Input:
fCGEhfHvcRouHzNw, gtjBkhfHvcRouHee

Ex Output:

hfHvcRouH