In this task, you are given two strings A, B. Find the longest common substring in the strings A and B.

Q: koddLvYmRXDUuUnW, GnqDYGmmRXDUuUquAnf

A: mRXDUuU
****
Q: UysTOtIRtRorNAFKKYD, icDOtIRtRoropYVaKzJ

A: OtIRtRor
****
Q: QGYcBv, fBYcXj

A:
Yc
****