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

Ex Input:
ilgSzrcUKLTNLJbMKMKSt, hFXIuUKLTNLJbMKWxSCkDjY

Ex Output:
UKLTNLJbMK


Ex Input:
zeuyZKwvIOfx, BlmZKwvspUt

Ex Output:
ZKwv


Ex Input:
LZxgUVAJoNUwOZ, FItxgUVAJoSV

Ex Output:

xgUVAJo