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

[EX Q]: UiaECWZf, gRyaECWLGRl
[EX A]: aECW

[EX Q]: kWnjCoVmCSVuW, RILPKCoVmCSVbaOza
[EX A]: CoVmCSV

[EX Q]: BWdpoKAUzlYfA, ipVTCPoKAUzliYnl
[EX A]:
oKAUzl

