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

[EX Q]: UysTOtIRtRorNAFKKYD, icDOtIRtRoropYVaKzJ
[EX A]: OtIRtRor

[EX Q]: wnIFoRQvMMKMAqpCQYncuWUTJs, bPMUKKxYRxQvMMKMAqpCmzAPPMD
[EX A]: QvMMKMAqpC

[EX Q]: mvweKfvk, pEgweKnZ
[EX A]:
weK