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

[Q]: BpGFyhLez, DfFyhuJY
[A]: Fyh


[Q]: XZslQqrShfCXRXyHrFVq, BtOQgQqrShfCXRRCRbMvXPM
[A]: QqrShfCXR


[Q]: bXkhBnbwStBSLfrE, jwFIXnbwStBoGI
[A]:
nbwStB