TASK DEFINITION: In this task, you are given two strings A, B. Find the longest common substring in the strings A and B.
PROBLEM: iwSQnplQZFbXQ, lHWnplQZFzswgU

SOLUTION: nplQZF

PROBLEM: zbSNNVc, agSNNtOQ

SOLUTION: SNN

PROBLEM: FzPTYG, HcPTvT

SOLUTION:
PT