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

Ex Input:
cZSEmdgP, YsSEmEIM

Ex Output:
SEm


Ex Input:
uDaqoOpUtLDdTGTO, ncIgBjDPqoOpUtLDdTNtiEyarDO

Ex Output:
qoOpUtLDdT


Ex Input:
FFtVkg, rRtVYa

Ex Output:

tV