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

XjYkMfARxWBSBjuXyDrFt, EtUxIfiHkMfARxWBSckTLTTnR
kMfARxWBS

VpJvIZdkzKovjc, BZEizZdkzKYZ
ZdkzK

FSLuQwTnVwoOaJnpANy, vjDjfYVwoOaJnplMzeo

VwoOaJnp