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

SOLUTION: yQYdx

PROBLEM: QRPOwtZATjDoJDdRNNSOH, wiafFMwpAjDoJDdRNNuCDZ

SOLUTION: jDoJDdRNN

PROBLEM: MnEkSYLQ, TROEkSLZ

SOLUTION:
EkS