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

yOGvgtAmwMwcIRtJ, cQtAmwMwcIRjfjO
tAmwMwcIR

OjQHcFUCflYUptUPqYKVomn, GXHcFUCflYUpSSTrQ
HcFUCflYUp

gzuVcixtZuwzBOxNT, ExixtZuwXKLY

ixtZuw