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

Example Input: goyZUz, QryZlD
Example Output: yZ

Example Input: UysTOtIRtRorNAFKKYD, icDOtIRtRoropYVaKzJ
Example Output: OtIRtRor

Example Input: dMswjMglEMSzCMnTjEmjFa, LfvIwjMglEMSzCDfaEPUe
Example Output:
wjMglEMSzC