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

gWMyioGBRpwcXfr, AOQGBRpwcSccqBE
GBRpwc

mRVieYomZqJXaTDsShCyfPW, ifOAlnptmZqJXaTDsVMqY
mZqJXaTDs

UlApxEmNcBtvKu, nSSApxEmNcKYAoAU

ApxEmNc