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

cvZfWOwa, xOfWOhZs
fWO

inquDFuJxtBaaFGCaRzO, NYcnWDuDFuJxtBafxZWCUw
uDFuJxtBa

zTZlbxpxUdbQBiKfZMACJwSkW, hrhKWmOvbQBiKfZMACFpdqBVoOv

bQBiKfZMAC