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

IIbJjQKWaoGKHGgWPcy, uNoMWaoGKHGqbnjmYQ
WaoGKHG

uDaqoOpUtLDdTGTO, ncIgBjDPqoOpUtLDdTNtiEyarDO
qoOpUtLDdT

cuKrtLmdCYPGo, NNqrarKrtLmdCYPPE

KrtLmdCYP