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

Ex Input:
goyZUz, QryZlD

Ex Output:
yZ


Ex Input:
lrBJDRkT, jmBJDrI

Ex Output:
BJD


Ex Input:
iiFVrmvzuYPY, dnSdWrmvzuSNQ

Ex Output:

rmvzu