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

Q: cfvqbAUpWEmhCSFaUvGrYVNGeUiRP, hAxWMEmhCSFaUvGLBLmdTxhy

A: EmhCSFaUvG
****
Q: vMYfFo, EHYfnP

A: Yf
****
Q: gARsideO, qRpRsiSNN

A:
Rsi
****