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

SOLUTION: oJ

PROBLEM: HaIPcFXLhYDp, AdIPcFXtJdRE

SOLUTION: IPcFX

PROBLEM: MCFJBY, DEFJWF

SOLUTION:
FJ