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

SOLUTION: ERnjubLF

PROBLEM: cUCQXEFSgRZjK, RYdvUQXEFSgRZVlwx

SOLUTION: QXEFSgRZ

PROBLEM: wSkKLxPUTbLboN, PQUxPUTbvBTf

SOLUTION:
xPUTb