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

Ex Input:
dmigbcBoWdAIyaeE, zXiKQFbcBoWdAIyaEypIjJpwbU

Ex Output:
bcBoWdAIya


Ex Input:
IGHhMfqLeBpnullsPInfBH, LTDBpnullsPIBynwCrCQ

Ex Output:
BpnullsPI


Ex Input:
FFumdUddWJInP, JOUddWJvU

Ex Output:

UddWJ