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

SOLUTION: rQ

PROBLEM: gWMyioGBRpwcXfr, AOQGBRpwcSccqBE

SOLUTION: GBRpwc

PROBLEM: kwJOJSqNGCStsyYyZezf, RiUjPPfPSqNGCStsyYqDgTfP

SOLUTION:
SqNGCStsyY